UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM N-CSR

              CERTIFIED SHAREHOLDER REPORT OF REGISTERED MANAGEMENT
                              INVESTMENT COMPANIES

                  Investment Company Act file number 811-06495
                                                    ----------------------------

       FLAHERTY & CRUMRINE PREFERRED INCOME OPPORTUNITY FUND INCORPORATED
--------------------------------------------------------------------------------
               (Exact name of registrant as specified in charter)

                      301 E. Colorado Boulevard, Suite 720
                               PASADENA, CA 91101
--------------------------------------------------------------------------------
               (Address of principal executive offices) (Zip code)

                               Donald F. Crumrine
                        Flaherty & Crumrine Incorporated
                      301 E. Colorado Boulevard, Suite 720
                               PASADENA, CA 91101
--------------------------------------------------------------------------------
                     (Name and address of agent for service)

        registrant's telephone number, including area code: 626-795-7300
                                                           -------------

                      Date of fiscal year end: NOVEMBER 30
                                              ------------

                     Date of reporting period: MAY 31, 2007
                                              -------------

Form N-CSR is to be used by management investment companies to file reports with
the Commission not later than 10 days after the  transmission to stockholders of
any report that is required to be transmitted to  stockholders  under Rule 30e-1
under the Investment Company Act of 1940 (17 CFR 270.30e-1).  The Commission may
use the information provided on Form N-CSR in its regulatory, disclosure review,
inspection, and policymaking roles.

A registrant  is required to disclose the  information  specified by Form N-CSR,
and the  Commission  will make this  information  public.  A  registrant  is not
required to respond to the  collection  of  information  contained in Form N-CSR
unless the Form  displays a  currently  valid  Office of  Management  and Budget
("OMB")  control number.  Please direct comments  concerning the accuracy of the
information  collection  burden  estimate and any  suggestions  for reducing the
burden to  Secretary,  Securities  and Exchange  Commission,  100 F Street,  NE,
Washington,  DC 20549. The OMB has reviewed this collection of information under
the clearance requirements of 44 U.S.C. ss. 3507.



ITEM 1. REPORTS TO STOCKHOLDERS.

The Report to Shareholders is attached herewith.

FLAHERTY & CRUMRINE PREFERRED INCOME OPPORTUNITY FUND


To the Shareholders of the Flaherty & Crumrine Preferred Income Opportunity Fund
("PFO"):

     The following  table  summarizes the Fund's  performance in its most recent
fiscal quarter and over longer time periods  compared with the average return of
investment-grade, fixed-income closed-end funds:
--------------------------------------------------------------------------------


                       TOTAL RETURN ON NET ASSET VALUE(1)
                         FOR PERIODS ENDED MAY 31, 2007

                                         ACTUAL RETURNS             AVERAGE ANNUALIZED RETURNS
                                  -------------------------   -------------------------------------
                                   THREE     SIX      ONE      THREE     FIVE      TEN      LIFE OF
                                   MONTHS   MONTHS    YEAR     YEARS     YEARS    YEARS     FUND(2)
                                  -------- --------  ------   ------     ------   ------   ------
                                                                      
Flaherty & Crumrine Preferred
Income Opportunity Fund ......... -2.4%     -0.9%     7.5%     6.6%      9.5%     8.1%     9.6%
Lipper Domestic Investment
Grade Funds(3) ..................  0.3%      1.9%     8.4%     6.0%      6.3%     6.7%     6.9%

----------------
(1) Based on monthly data provided by Lipper Inc. in each calendar  month during
    the  relevant  period. Distributions are  assumed to be reinvested at NAV in
    accordance  with Lipper's practice, which differs from the  methodology used
    elsewhere in this report.
(2) Since inception on February 13, 1992.
(3) Includes all closed-end funds in Lipper's U.S. Government, U.S. Mortgage and
    Corporate  Debt  BBB  Rated  categories  in  each  month  during the period.
    Although the investment  strategies  used by the  Fund  differ significantly
    from  the strategies used by these other fixed-income  funds, the Fund seeks
    to achieve a similar income goal.


--------------------------------------------------------------------------------
     While the Fund did not perform as well as the Lipper  group of funds during
recent periods, it has outperformed this group over all longer time periods. The
Fund's  performance was impacted by a number of factors,  and we've discussed in
greater  detail the total  return for the most  recent  six-month  period in the
Questions and Answers  section that follows.  Stated in short,  primarily due to
rising long-term interest rates over the six-month period, the Fund's securities
portfolio  only had a modest  positive  return,  which was reduced by its use of
leverage  and the  overall  expenses  of  operating  the Fund.  Over longer time
periods, the Fund's use of leverage has benefited its common  shareholders,  not
only by offsetting the Fund's expenses, but by increasing the total return.

     These days we spend a lot of time  assessing  the  likelihood  of a company
being  purchased  in a leveraged  buyout  (LBO).  Billions of dollars are in the
hands of LBO firms, fueled by their ability to borrow at historically low rates.
As  discussed  in greater  detail in the  Questions  and  Answers  section  that
follows,  the economics of these  buyouts have changed over the years,  and many
more companies - including  issuers of preferred  securities - are now potential
targets.

     Another  type of risk  receiving a lot of  attention  these days is fallout
from weakness in the housing sector.  We've discussed this in previous  letters,
but recently the market has refocused on subprime loans.  Suffice it to say, the
Fund continues to have no direct exposure to subprime lenders. While some of the
bank and financial companies we invest in will certainly be impacted by weakness
in the housing sector, in each case the impact still appears to be manageable.



     Our  investment  process  relies  heavily  on  in-depth  credit  research -
understanding  as much as we can about the  companies  we  invest  in,  from the
financial  statements to the philosophy of management to more current risks like
LBOs and subprime  exposure.  That being said,  we don't mind taking risk in our
portfolio  as  long  as we  understand  it  and  feel  we are  being  adequately
compensated.

     The  universe  of  preferred  stock  eligible  for the  dividends  received
deduction  (DRD) remains in relatively  tight supply.  We do see new issues from
time to time,  but the general  trend  continues  to be shrinkage in this market
segment.  Of  course,  this  makes the DRD  issues  owned by the Fund a bit more
precious, but it also makes it difficult to find new securities to buy. We don't
expect this segment to disappear,  but relative to the broader preferred market,
it  should  continue  to  contract.  DRD  issues  continue  to be among the best
performers in the fixed-income markets.

     In contrast to the DRD market,  the market for fully-taxable  preferreds is
in full bloom.  There are often two or three new issues a week, and they tend to
be pretty sizable.  The lion's share of these new issues has been the "enhanced"
variety  we've  discussed  in the past (and  described  more fully on the Fund's
website).  In the two years since this  structure  was  developed,  close to one
hundred  new  issues,  with a market  value of roughly  $75  billion,  have been
created.  It's harder to generalize about  performance of the taxable  preferred
sector because of the wide variety of issuers and issue types, but it has mostly
been a mixed bag.  The Fund's  portfolio  has  generally  mirrored  the  overall
market, but we think it should outperform over time.

     Since  preferred  securities are connected at the hip to the U.S.  Treasury
market, a quick recap of that market is useful.  Over the three months ended May
31st,  the Treasury  "curve" (the plot of yields versus  maturity)  twisted,  as
shorter-term rates fell modestly and intermediate and long-term rates increased.
With intermediate and long-term rates continuing to increase since May 31st, the
curve now has a more "normal" shape,  with rates on longer maturity issues above
those of shorter  issues.  Since March,  intermediate  and long-term  rates have
risen as a result of a combination of factors,  including:  a resurging domestic
economy   following   a  weak   first   quarter,   increasing   interest   rates
internationally  and subsequent reduced investment flows from overseas,  and the
market's  declining  expectation  of the  Federal  Reserve  lowering  short-term
interest rates.

     Sometimes  the ride can be a little bumpy when the yield curve goes through
a transition  like this,  but in the long run, the Fund should  benefit.  In the
short run, we anticipate  that the Fund's "safety net" hedging  strategy  should
make the Fund's  investment  portfolio  progressively  less sensitive to further
increases in long-term  interest rates. In addition,  higher interest rates also
reduce the exposure of the Fund's holdings to early redemption,  as the issuer's
cost of funding these calls  increases.  In turn, this reduced exposure to early
redemption enhances the Fund's ability to pay its current dividend.

                                       2



     The  Questions and Answers  section that follows and the Fund's  website at
www.preferredincome.com  have more  complete  discussions  of a number of topics
that may interest you. The topics on the website include our overall  assessment
of the state of the economy and interest rates (in our Second  Quarter  Economic
Update) and an archive of frequently-asked questions which remain relevant today
- including  an in-depth  discussion  of the risks of  subprime  mortgages,  our
interest-rate  hedging strategy and our use of leverage.  We believe an informed
shareholder can be one of the strongest assets of any company,  and we encourage
you to explore the website for a wide range of additional information about your
Fund.

Sincerely,

/S/ DONALD F. CRUMRINE     /S/ ROBERT M. ETTINGER
Donald F. Crumrine         Robert M. Ettinger
Chairman of the Board      President

July 17, 2007

                                       3



                              QUESTIONS & ANSWERS

WHAT WERE THE COMPONENTS OF THE FUND'S TOTAL RETURN ON NET ASSET VALUE?

     PFO's  investment  objective is to produce high current  income  consistent
with preservation of capital.  While shareholder  returns are more directly tied
to the market  price of the Fund's  shares,  we believe  that  shareholders  can
assess  whether  the  Fund's  investment   objective  is  being  met  by  better
understanding the Fund's total return on net asset value (NAV).

     As a closed-end  fund,  PFO utilizes a variety of investment  tools to meet
its objective,  namely: (a) investing in a portfolio of securities;  (b) hedging
that portfolio of securities against significant increases in long-term interest
rates;  and (c) issuing an auction-rate  preferred stock to leverage and enhance
returns to Common Stock shareholders. The table below reviews the performance of
each of those tools over the Fund's fiscal year-to-date and then adjusts for the
impact of the Fund's  expenses to arrive at a total return on NAV (which factors
in all of these items).

                     COMPONENTS OF PFO'S TOTAL RETURN ON NAV
                        FOR SIX MONTHS ENDED MAY 31, 2007
--------------------------------------------------------------------------------
Total Return on Securities Portfolio (including principal and income) ...  0.8%

Return from Interest Rate Hedging Strategy .............................. (0.2)%

Impact of Leverage ...................................................... (0.7)%

Expenses ................................................................ (0.8)%
--------------------------------------------------------------------------------
                                               TOTAL RETURN ON NAV        (0.9)%

     Intermediate  and  long-term  U.S.  Treasury  bond  yields  increased - and
consequently, their market value decreased - during the first half of the Fund's
fiscal year. Like all  fixed-income  securities,  the value of preferred  stocks
typically  moves in relation to U.S.  Treasury  bonds and this is what  happened
during the past six months,  with the Fund's  securities  portfolio  losing some
principal  value.  Nonetheless,  the portfolio did have a positive  total return
through the income  produced by its securities  portfolio.  Since interest rates
did not increase  significantly  until the very end of this  period,  the Fund's
interest-rate  hedging strategy had a minimal negative effect on the portfolio's
results.

     While  leverage had a modest  negative  impact on the Fund's returns during
this six-month period,  over longer time periods leverage has made a significant
positive  contribution  to  the  Fund's  Common  Stock  shareholders.  The  Fund
continues  to  have   approximately  the  same  expense  ratio  as  it  has  had
historically, which results in the Fund having a slightly negative return on NAV
during this six-month period.

HOW DOES THE FUND MANAGE THE RISK OF LEVERAGED BUYOUTS?

     Leveraged buyouts (LBOs) and management  buyouts (MBOs) have long presented
risks to  investment-grade  fixed-income  investors.  However,  buyouts had been
relatively  rare  among  the  largest   preferred   issuers,   namely  financial
institutions  (because  they are already  inherently  leveraged)  and  utilities
(because  they are  heavily  regulated  with only  modest  returns  on  equity).
Recently,  the risk of higher leverage resulting from an LBO or MBO has expanded
into these industries. For example, among utilities, Duquesne Light Holdings was
acquired by a buyout fund and Texas  Utilities  has agreed to be  purchased by a
consortium of private-equity firms. Among financial companies,  SLM Corporation,
or Sallie Mae, also has 9agreed to a buyout.  These transactions have heightened
the LBO risks for preferred and debt investors in industries that previously had
been considered largely "immune" to LBOs.

                                       4



     There are many reasons why the reach of  leveraged  buyouts has expanded in
recent years.  First,  LBO funds are much larger now than in the past.  They can
buy larger companies and more of them.  Second,  as they have grown in size, the
marginal return required by the funds appears to have declined. This has put "in
play" companies that previously would have been rejected as offering  inadequate
equity returns.  Third,  the regulatory  environment  has turned  decidedly more
"laissez-faire"  over the past decade.  Buyouts that most likely would have been
rejected by regulators ten years ago now stand a good chance of approval as long
as buyers can  demonstrate  that consumers  (rather than holders of preferred or
debt securities) will not be harmed.

     In a  typical  LBO,  the  new  owner - often  a  private  entity  such as a
private-equity  fund - buys out existing common shareholders at a premium to the
company's pre-deal market value. The purchase price is financed by a combination
of  equity  contributed  by the  buyer  and new debt  issued  to  investors.  As
indicated by the name  "leveraged  buyout,"  debt  comprises the majority of the
buyout  financing.  In most cases,  existing  debt and  preferreds at the target
company are assumed by the new, now much more highly leveraged  entity.  This is
clearly bad news for existing preferred holders. Most or all of the newly issued
debt will be senior to preferreds in the company's capital  structure.  The same
thing may be true for existing  senior debt as well, if the LBO sponsor  decides
to issue senior secured debt ahead of the senior  unsecured  debt. No matter how
the deal is  structured,  the  combination  of higher  leverage and  potentially
greater subordination  typically leaves existing debt and preferred holders with
riskier securities.  Issues that might have been rated BBB+ could easily drop to
BB or even B.  Naturally,  investors  require  higher yields for the  additional
credit risk in the lower-rated securities, so existing debt and preferred issues
must fall in price - to the detriment of owners of those securities.

     We take these risks very  seriously,  and there are several ways we address
them in the Fund's portfolios. Some preferred and debt issues contain "change of
control"  provisions that require the company either to redeem the security at a
predetermined  price or to pay a  significantly  higher coupon if the company is
acquired  and its  ratings  fall  below a certain  level  (typically  investment
grade).  Given the heightened LBO risk in recent months, more new issues contain
this  provision  than in the  past,  although  they are  still  very much in the
minority.  As much as we like these  provisions,  few older issues contain them,
especially  among the bank,  finance,  and utility  securities  that make up the
majority of the Fund's holdings. As a result, it would be impossible to assemble
a  diversified  - not to mention  attractively  priced - portfolio of securities
comprised solely of such issues.

     The most  important  ways we  manage  LBO risk are the same  ways we manage
credit risk in general:  We do rigorous  credit  analysis on the companies whose
securities  we own or would  consider  owning,  and we diversify our holdings by
industry,  business line, and company. As the reach of buyout firms has extended
into the  sectors in which we are  preferred  investors,  we are  undertaking  a
thorough review of the credits in the Fund's portfolio, with a particular eye to
LBO risk.

     We ask ourselves,  "Can this company be leveraged to produce higher returns
to equity  holders?"  The answer to this  question  requires  an  analysis  of a
company's  assets,  earnings  and  cash  flow,  capital  structure,   regulatory
environment and market valuation.  Our judgments about these matters guide us to
an assessment of LBO risk for a particular issuer. Combining that with the terms
of a particular  security leads us to an assessment of that security's LBO risk.
If we  conclude  that an  issuer is an  attractive  LBO  candidate  and that its
preferred  securities would be unprotected in the event of an LBO, we would seek
to sell (or avoid  buying) the  preferred  securities  of that issuer or utilize
other  measures to mitigate  the LBO risk in owning  that  particular  security.
Indeed, we have sold preferred securities positions where we think LBO risk is

                                       5



uncomfortably high. Of course,  if  the  Fund  had  a  common  stock  investment
strategy,  we might make the opposite decision given that common stock investors
are typically  rewarded in the event of an LBO.

     Fund  shareholders  should be aware  that this  sort of  analysis  is not a
science.  We cannot plug  variables  into an equation and arrive at a conclusive
measurement  of LBO risk;  we cannot  say with  certainty  that an issue that we
judge to be at low risk of LBO will not be subject to a leveraged  buyout in the
future.  There  are too many  variables  - many of which are  unobservable  - to
construct such an analysis.  Nonetheless, we believe this credit-driven approach
will  help us to  reduce  the risk of LBOs to the  Fund's  holdings,  and it has
become an important element of our portfolio management process.

                                       6



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                                              PORTFOLIO OVERVIEW
                                                        MAY 31, 2007 (UNAUDITED)
              ------------------------------------------------------------------


FUND STATISTICS ON 5/31/07
------------------------------------------------
Net Asset Value                $        12.10

Market Price                   $        12.13

Premium                                  0.25%

Yield on Market Price                    6.43%

Common Stock Shares
Outstanding                        11,721,854


INDUSTRY CATEGORIES        % OF PORTFOLIO
--------------------------------------------
                                [GRAPHIC OMITTED]
     EDGAR REPRESENATION OF DATA POINTS USED IN PRINTED GRAPHIC AS FOLLOWS:

REITs               4%
Energy              8%
Other               3%
Financial Services 10%
Utilities          35%
Banking            23%
Insurance          17%


MOODY'S RATINGS   % OF PORTFOLIO
-------------------------------------
AAA                            0.0%

AA                             3.3%

A                             15.6%

BBB                           59.3%

BB                            11.3%

Not Rated                      8.2%
-------------------------------------
Below Investment Grade*       14.1%
* BELOW INVESTMENT GRADE BY BOTH MOODY'S AND
  S&P.


TOP 10 HOLDINGS BY ISSUER  % OF PORTFOLIO
-------------------------------------------
Interstate Power & Light             4.8%

Liberty Mutual Group                 4.1%

Xcel Energy                          3.6%

Goldman Sachs                        3.5%

Public Storage                       3.3%

First Republic Bank                  3.1%

EOG Resources                        3.1%

Cobank                               2.9%

Banco Santander                      2.8%

HSBC                                 2.7%




                                                                                      % OF PORTFOLIO**
-------------------------------------------------------------------------------------------------------
                                                                                              
Holdings Generating Qualified Dividend Income (QDI) for Individuals                              64%

Holdings Generating Income Eligible for the Corporate Dividends Received Deduction (DRD)         56%
-------------------------------------------------------------------------------------------------------
** THIS DOES NOT REFLECT YEAR-END RESULTS OR ACTUAL TAX  CATEGORIZATION  OF FUND
   DISTRIBUTIONS.  THESE PERCENTAGES CAN, AND DO, CHANGE, PERHAPS SIGNIFICANTLY,
   DEPENDING  ON MARKET  CONDITIONS.  INVESTORS SHOULD CONSULT THEIR TAX ADVISOR
   REGARDING THEIR PERSONAL SITUATION.


                                       7



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
PORTFOLIO OF INVESTMENTS
MAY 31, 2007 (UNAUDITED)
------------------------------------------------------------------




SHARES/$ PAR                                                                                        VALUE
-------------                                                                                      -------
                                                                                        
PREFERRED SECURITIES -- 94.1%
                BANKING -- 22.6%
----------------------------------------------------------------------------------------------------------------
$    3,000,000  Astoria Capital Trust I, 9.75% 11/01/29, Series B .............................  $     3,372,384
                Banco Santander:
        17,000     Adj. Rate Pfd., 144A**** ...................................................          399,840**(1)
       165,600     6.50% Pfd., 144A**** .......................................................        4,058,856**(1)
        56,800     6.80% Pfd., 144A**** .......................................................        1,425,680**(1)
$    3,000,000  CBG Florida REIT Corporation, 7.114%, 144A**** ................................        2,983,800
        19,648  Citizens Funding Trust I, 7.50% Pfd. 09/15/66 .................................          509,007
                Cobank, ACB:
        45,000     7.00% Pfd., 144A**** .......................................................        2,264,490*
        75,000     7.814% Pfd., 144A**** ......................................................        3,957,375*
$      700,000  Comerica Capital Trust II, 6.576%, 02/30/37 ...................................          673,217
$      500,000  Comerica (Imperial) Capital Trust I, 9.98% 12/31/26, Series B .................          527,424
         4,500  FBOP Corporation, Adj. Rate Pfd., 144A**** ....................................        4,629,375*
$    2,250,000  First Hawaiian Capital I, 8.343% 07/01/27, Series B ...........................        2,347,164(1)
                First Republic Bank:
       200,000     6.25% Pfd. .................................................................        5,106,260*
         5,000     6.70% Pfd. .................................................................          129,062*
           640  First Republic Preferred Capital Corporation, 10.50% Pfd., 144A**** ...........          719,616
        22,500  First Republic Preferred Capital Corporation II, 8.75% Pfd., Series B, 144A****          581,850
         5,000  Fleet Capital Trust VIII, 7.20% Pfd. 03/15/32 .................................          127,344
$      500,000  HBOS PLC, 6.657%, 144A**** ....................................................          488,750**(1)
         5,000  HSBC Series II, Variable Inverse Pfd., Pvt. ...................................        5,675,000*
         2,500  HSBC USA, Inc., $2.8575 Pfd. ..................................................          126,016*
        12,000  Keycorp Capital VIII, 7.00% Pfd. 06/15/66 .....................................          310,876
        45,000  Keycorp Capital IX, 6.75% Pfd. 12/15/66 .......................................        1,136,250
         5,000  National City Capital Trust II, 6.625% Pfd. 11/15/36 ..........................          123,906
        16,000  PFGI Capital Corporation, 7.75% Pfd. ..........................................          412,480
$      650,000  RBS Capital Trust B, 6.80% ....................................................          640,705**(1)
$      800,000  Regions Financing Trust II, 6.625%, 05/15/47 ..................................          781,370
            10  Roslyn Real Estate, 8.95% Pfd., Series C, 144A**** ............................        1,073,577
        70,500  Sovereign Bancorp, 7.30% Pfd., Series C .......................................        1,912,313*
        20,375  Sovereign Capital Trust V, 7.75% Pfd. 05/22/36 ................................          533,570
         6,000  USB Capital XI, 6.60% Pfd. 09/15/66 ...........................................          152,160
----------------------------------------------------------------------------------------------------------------
                                                                                                      47,753,017
                                                                                                 ---------------


    The accompanying notes are an integral part of the financial statements.
                                       8



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                            PORTFOLIO OF INVESTMENTS (CONTINUED)
                                                        MAY 31, 2007 (UNAUDITED)
              ------------------------------------------------------------------




SHARES/$ PAR                                                                                        VALUE
-------------                                                                                      -------
                                                                                        
PREFERRED SECURITIES -- (CONTINUED)
                FINANCIAL SERVICES -- 9.9%
----------------------------------------------------------------------------------------------------------------
        36,500  Cabco Trust For Goldman Sachs Capital I, Adj. Rate Pfd. 02/15/34 ..............  $       880,106
$    2,500,000  CIT Group Inc, 6.10% ..........................................................        2,342,780
                Goldman Sachs:
            25     Pass-Through Certificates, Class B, 144A**** ...............................        2,764,000*
         3,500     STRIPES Custodial Receipts, Pvt. ...........................................        3,853,500*
         3,000  Merrill Lynch Series II STRIPES Custodial Receipts, Pvt. ......................        3,096,000*
        72,000  Merrill Lynch & Company, Adj. Rate Pfd., Series 5 .............................        1,822,500*
        47,000  Morgan Stanley Capital Trust VI, 6.60% Pfd. ...................................        1,185,284(2)
                SLM Corporation:
        94,150     6.97% Pfd., Series A .......................................................        4,755,517*
         4,000     Adj. Rate Pfd., Series B ...................................................          352,000*
                U.S. Bancorp, Auction Pass-Through Trust, Cl. B:
         9         Series 2006-5, Variable Rate Pfd., 144A**** ................................          286,650*
         9         Series 2006-6, Variable Rate Pfd., 144A**** ................................          286,650*
----------------------------------------------------------------------------------------------------------------
                                                                                                      21,051,687
                                                                                                 ---------------
                INSURANCE -- 14.8%
----------------------------------------------------------------------------------------------------------------
        20,000  ACE Ltd., 7.80% Pfd., Series C ................................................          515,000**(1)
$    4,250,000  AON Capital Trust A, 8.205% 01/01/27 ..........................................        4,651,693
                Arch Capital Group Ltd.:
        10,000     7.875% Pfd., Series B ......................................................          260,625**(1)
        24,400     8.00% Pfd., Series A .......................................................          643,550**(1)
$    2,500,000  AXA SA, 6.463%, 144A**** ......................................................        2,406,907**(1)
                Axis Capital Holdings:
        12,100     7.25% Pfd., Series A .......................................................          310,819**(1)
        14,700     7.50% Pfd., Series B .......................................................        1,517,040(1)
        22,300  Berkley W.R. Capital Trust II, 6.75% Pfd. 07/26/45 ............................          560,985
        50,000  Delphi Financial Group, 7.376% Pfd., 05/15/37 .................................        1,239,065
         5,750  Everest Re Capital Trust II, 6.20% Pfd., Series B .............................          136,634
$      935,000  Everest Reinsurance Holdings, 6.60%, 05/15/37 .................................          918,479
$    4,500,000  Liberty Mutual Group, 7.80%, 03/15/37, 144A**** ...............................        4,387,590
       175,000  Principal Financial Group, 6.518% Pfd. ........................................        4,850,790*
$      511,000  Provident Financing Trust I, 7.405% 03/15/38 ..................................          514,325
       105,000  Renaissancere Holdings Ltd., 6.60% Pfd., Series D .............................        2,559,900**(1)
       115,500  Scottish Re Group Ltd., 7.25% Pfd. ............................................        2,721,469**(1)
$    1,060,000  USF&G Capital, 8.312% 07/01/46, 144A**** ......................................        1,281,964


    The accompanying notes are an integral part of the financial statements.
                                       9



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
PORTFOLIO OF INVESTMENTS (CONTINUED)
MAY 31, 2007 (UNAUDITED)
------------------------------------------------------------------




SHARES/$ PAR                                                                                        VALUE
-------------                                                                                      -------
                                                                                        
PREFERRED SECURITIES -- (CONTINUED)
                INSURANCE -- (CONTINUED)
----------------------------------------------------------------------------------------------------------------
                XL Capital Ltd.:
$    1,400,000     6.50%, Series E ............................................................  $     1,346,226(1)
        22,850     8.00% Pfd., Series A .......................................................          583,390**(1)
----------------------------------------------------------------------------------------------------------------
                                                                                                      31,406,451
                                                                                                 ---------------
                UTILITIES -- 34.9%
----------------------------------------------------------------------------------------------------------------
                Alabama Power Company:
         4,980     4.60% Pfd. .................................................................          415,531*
         6,485     4.72% Pfd. .................................................................          555,246*
           868     4.92% Pfd. .................................................................           77,469*
         6,579  Baltimore Gas & Electric Company, 6.70% Pfd., Series 1993 .....................          681,749*
        74,270  Calenergy Capital Trust III, 6.50% Pfd. 09/01/27 ..............................        3,582,785
         1,628  Central Hudson Gas & Electric Corporation, 4.35% Pfd., Series D, Pvt. .........          125,812*
         3,798  Central Maine Power Company, 4.75% Pfd. .......................................          305,587*
         8,339  Central Vermont Public Service Corporation, 8.30% Sinking Fund Pfd., Pvt. .....          866,255*
                Connecticut Light & Power Company:
         2,050     4.50% Pfd., Series 1956 ....................................................           79,171*
        10,000     4.50% Pfd., Series 1963, Pvt. ..............................................          384,200*
        25,000     5.28% Pfd., Series 1967 ....................................................        1,138,000*
           883     $2.04 Pfd., Series 1949 ....................................................           30,923*
         2,900     $2.20 Pfd., Series 1949 ....................................................          109,533*
         9,652     $3.24 Pfd. .................................................................          505,572*
         2,000  Consolidated Edison Company of New York, 4.65% Pfd., Series C .................          169,560*
         7,500  Dayton Power and Light Company, 3.90% Pfd., Series C ..........................          486,825*
        23,000  Dominion CNG Capital Trust I, 7.80% Pfd. ......................................          581,470
$    1,500,000  Dominion Resources Capital Trust III, 8.40% 01/15/31 ..........................        1,794,042
        15,030  Duquesne Light Company, 3.75% Pfd. ............................................          462,623*
                Entergy Arkansas, Inc.:
         2,840     4.56% Pfd. .................................................................          224,900*
         3,050     4.56% Pfd., Series 1965 ....................................................          241,529*
         1,435     6.08% Pfd. .................................................................          143,041*
        90,000    6.45% Pfd. ..................................................................        2,316,600*
         2,441  Entergy Gulf States, Inc., 7.56% Pfd. .........................................          234,629*
        36,000  Entergy Louisiana, Inc., 6.95% Pfd. ...........................................        3,661,200*
                Entergy Mississippi, Inc.:
         4,616     4.36% Pfd. .................................................................          320,720*
         5,000     4.92% Pfd. .................................................................          392,050*


    The accompanying notes are an integral part of the financial statements.
                                       10



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                            PORTFOLIO OF INVESTMENTS (CONTINUED)
                                                        MAY 31, 2007 (UNAUDITED)
              ------------------------------------------------------------------




SHARES/$ PAR                                                                                        VALUE
-------------                                                                                      -------
                                                                                        
PREFERRED SECURITIES -- (CONTINUED)
                UTILITIES -- (CONTINUED)
----------------------------------------------------------------------------------------------------------------
         4,400  Florida Power Company, 4.75% Pfd. .............................................  $       373,296*
        68,500  FPC Capital I, 7.10% Pfd., Series A ...........................................        1,721,576
        69,250  FPL Group Capital, Inc., 6.60% Pfd. 10/01/66, Series A ........................        1,766,741
         8,900  Georgia Power, 6.125% Pfd. ....................................................          226,238*
                Great Plains Energy, Inc.:
         1,625     4.20% Pfd. .................................................................          121,696*
         2,000     4.35% Pfd. .................................................................          155,120*
                Hawaiian Electric Company, Inc.:
         2,471     5.00% Pfd., Series D .......................................................           42,161*
         7,438     5.00% Pfd., Series E .......................................................          126,911*
         1,383     5.00% Pfd., Series I .......................................................           23,597*
        30,500  Indianapolis Power & Light Company, 5.65% Pfd. ................................        2,803,560*
       340,000  Interstate Power & Light Company, 8.375% Pfd., Series B .......................       10,234,000*
         2,588  New York State Electric & Gas, $4.50 Pfd., Series 1949 ........................          208,748*
                Ohio Power Company:
         3,018     4.20% Pfd. .................................................................          230,122*
         1,251     4.40% Pfd. .................................................................           99,930*
                Pacific Enterprises:
        13,680     $4.36 Pfd. .................................................................        1,083,182*
        24,985     $4.50 Pfd. .................................................................        2,041,774*
        15,730     $4.75 Pfd., Series 53 ......................................................        1,356,870*
                Pacific Gas & Electric Co.:
         7,600     4.50% Pfd., Series H .......................................................          151,392*
        41,500     5.00% Pfd., Series D .......................................................          887,270*
        83,000     5.00% Pfd., Series E .......................................................        1,806,080*
                PacifiCorp:
         5,672     $4.56 Pfd. .................................................................          450,697*
         6,708     $4.72 Pfd. .................................................................          551,666*
         8,750     $7.48 Sinking Fund Pfd. ....................................................          891,133*
         1,250  PECO Energy Company, $4.30 Pfd., Series B .....................................           96,438*
$    1,500,000  PECO Energy Capital Trust III, 7.38% 04/06/28, Series D .......................        1,569,600
        12,748  Portland General Electric, 7.75% Sinking Fund Pfd. ............................        1,288,823*
        14,020  Public Service Electric & Gas Company, 5.28% Pfd., Series E ...................        1,344,238*
        70,210  San Diego Gas & Electric Company, $1.70 Pfd. ..................................        1,838,624*
                South Carolina Electric & Gas Company:
        13,974     5.125% Purchase Fund Pfd., Pvt. ............................................          718,124*
         7,774     6.00% Purchase Fund Pfd., Pvt. .............................................          395,774*


    The accompanying notes are an integral part of the financial statements.
                                       11



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
PORTFOLIO OF INVESTMENTS (CONTINUED)
MAY 31, 2007 (UNAUDITED)
------------------------------------------------------------------




SHARES/$ PAR                                                                                        VALUE
-------------                                                                                      -------
                                                                                        
PREFERRED SECURITIES -- (CONTINUED)
                UTILITIES -- (CONTINUED)
----------------------------------------------------------------------------------------------------------------
                Southern California Edison:
         5,000     4.24% Pfd. .................................................................  $        97,200*
        11,300     6.00% Pfd. .................................................................        1,121,638*
                Southern Union Company:
$      700,000     7.20% 11/01/66 .............................................................          707,115
        51,750     7.55% Pfd. .................................................................        1,327,905*
$      750,000  TXU Electric Capital V, 8.175% 01/30/37 .......................................          734,400
                Union Electric Company:
         5,700     4.56% Pfd. .................................................................          437,874*
        10,156     $7.64 Pfd. .................................................................        1,042,412*
                Virginia Electric & Power Company:
         1,665     $4.04 Pfd. .................................................................          119,514*
         2,470     $4.20 Pfd. .................................................................          184,311*
         1,673     $4.80 Pfd. .................................................................          142,673*
         3,878     $6.98 Pfd. .................................................................          394,587*
        12,500     $7.05 Pfd. .................................................................        1,263,673*
        44,200  Virginia Power Capital Trust, 7.375% Pfd. 07/30/42 ............................        1,124,338
         2,262  Washington Gas & Light Company, $4.25 Pfd. ....................................          179,422*
$    1,700,000  Wisconsin Energy Corporation, 6.25%, 05/15/67 .................................        1,658,596
        13,863  Wisconsin Power & Light Company, 6.20% Pfd. ...................................        1,423,124*
                Xcel Energy, Inc.:
        15,000     $4.08 Pfd., Series B .......................................................        1,133,250*
        20,040     $4.10 Pfd., Series C .......................................................        1,521,437*
        35,510     $4.11 Pfd., Series D .......................................................        2,702,311*
        17,750     $4.16 Pfd., Series E .......................................................        1,367,283*
        10,000     $4.56 Pfd., Series G .......................................................          836,800*
----------------------------------------------------------------------------------------------------------------
                                                                                                      74,012,266
                                                                                                 ---------------
                ENERGY -- 5.6%
----------------------------------------------------------------------------------------------------------------
         8,000  Devon Energy Corporation, 6.49% Pfd., Series A ................................          812,500*
$    2,300,000  Enterprise Products Partners, 7.034%, 01/15/68 ................................        2,285,703
         6,125  EOG Resources, Inc., 7.195% Pfd., Series B ....................................        6,486,436*
$    1,200,000  KN Capital Trust III, 7.63% 04/15/28 ..........................................        1,175,520
        10,000  Lasmo America Limited, 8.15% Pfd., 144A**** ...................................        1,055,400*(1)
----------------------------------------------------------------------------------------------------------------
                                                                                                      11,815,559
                                                                                                 ---------------


    The accompanying notes are an integral part of the financial statements.
                                       12



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                            PORTFOLIO OF INVESTMENTS (CONTINUED)
                                                        MAY 31, 2007 (UNAUDITED)
              ------------------------------------------------------------------




SHARES/$ PAR                                                                                        VALUE
-------------                                                                                      -------
                                                                                        
PREFERRED SECURITIES -- (CONTINUED)
                REAL ESTATE INVESTMENT TRUST (REIT) -- 4.2%
----------------------------------------------------------------------------------------------------------------
                BRE Properties, Inc.:
        12,600     6.75% Pfd., Series D .......................................................  $       315,000
        40,000     8.08% Pfd., Series B .......................................................        1,021,252
         1,000  Equity Residential Properties, 8.29% Pfd., Series K ...........................           57,940
                Public Storage, Inc.:
       121,975     6.45% Pfd., Series F .......................................................        2,950,270
        70,000     6.625% Pfd., Series M ......................................................        1,734,691
        10,000     6.95% Pfd., Series H .......................................................          255,000
        79,900     7.25% Pfd., Series K .......................................................        2,059,926
        20,000  Realty Income Corp., 6.75% Pfd., Series E .....................................          503,126
----------------------------------------------------------------------------------------------------------------
                                                                                                       8,897,205
                                                                                                 ---------------
                MISCELLANEOUS INDUSTRIES -- 2.0%
----------------------------------------------------------------------------------------------------------------
        13,600  E.I. Du Pont de Nemours and Company, $4.50 Pfd., Series B .....................        1,151,648*
        35,000  Ocean Spray Cranberries, Inc., 6.25% Pfd., 144A**** ...........................        3,047,800*
----------------------------------------------------------------------------------------------------------------
                                                                                                       4,199,448
                                                                                                 ---------------
                U.S. GOVERNMENT SECURITIES -- 0.1%
----------------------------------------------------------------------------------------------------------------
         4,450  Fannie Mae, 4.75% Series M ....................................................          192,073*
----------------------------------------------------------------------------------------------------------------
                                                                                                         192,073
                                                                                                 ---------------
                   TOTAL PREFERRED SECURITIES
                   (Cost $190,621,784) ........................................................      199,327,706
                                                                                                 ---------------
CORPORATE DEBT SECURITIES -- 4.9%
                INSURANCE -- 2.5%
----------------------------------------------------------------------------------------------------------------
$      900,000  Farmers Exchange Capital, 7.20% 07/15/48, 144A**** ............................          905,400
$    4,417,000  Liberty Mutual Insurance, 7.697% 10/15/97, 144A**** ...........................        4,398,449
----------------------------------------------------------------------------------------------------------------
                                                                                                       5,303,849
                                                                                                 ---------------
                UTILITIES -- 0.1%
----------------------------------------------------------------------------------------------------------------
        10,000  Entergy Louisiana LLC, 7.60% 04/01/32 .........................................          255,938
----------------------------------------------------------------------------------------------------------------


    The accompanying notes are an integral part of the financial statements.
                                       13



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
PORTFOLIO OF INVESTMENTS (CONTINUED)
MAY 31, 2007 (UNAUDITED)
------------------------------------------------------------------




SHARES/$ PAR                                                                                        VALUE
-------------                                                                                      -------
                                                                                        
CORPORATE DEBT SECURITIES -- (CONTINUED)
                ENERGY -- 2.3%
----------------------------------------------------------------------------------------------------------------
$    2,450,000  KN Energy, Inc., 7.45% 03/01/98 ...............................................  $     2,370,108
        97,900  Nexen, Inc., 7.35% Subordinated Notes .........................................        2,481,158(1)
----------------------------------------------------------------------------------------------------------------
                                                                                                       4,851,266
                                                                                                 ---------------
                TOTAL CORPORATE DEBT SECURITIES
                   (Cost $10,127,660) .........................................................       10,411,053
                                                                                                 ---------------
COMMON STOCK -- 0.1%
                BANKING -- 0.1%
----------------------------------------------------------------------------------------------------------------
        15,000  New York Community Bancorp, Inc. ..............................................          262,200*
----------------------------------------------------------------------------------------------------------------
                                                                                                         262,200
                                                                                                 ---------------
                TOTAL COMMON STOCK
                   (Cost $246,408) ............................................................          262,200
                                                                                                 ---------------
OPTION CONTRACTS -- 0.3%
           100  September Call Options On September U.S. Treasury Bond Futures,
                   Expiring 08/24/07 ..........................................................            9,375+
         1,400  September Put Options On September U.S. Treasury Bond Futures,
                   Expiring 08/24/07 ..........................................................          550,625+
----------------------------------------------------------------------------------------------------------------
                TOTAL OPTION CONTRACTS
                   (Cost $422,534) ............................................................          560,000
                                                                                                 ---------------
MONEY MARKET FUND -- 0.5%
     1,095,675  BlackRock Provident Institutional, TempFund ...................................        1,095,675
----------------------------------------------------------------------------------------------------------------
                TOTAL MONEY MARKET FUND
                   (Cost $1,095,675) ..........................................................        1,095,675
                                                                                                 ---------------
TOTAL INVESTMENTS (Cost $202,514,061***) ..............................................  99.9%       211,656,634
OTHER ASSETS AND LIABILITIES (Net) ....................................................   0.1%           128,161
                                                                                        ------   ---------------
TOTAL NET ASSETS AVAILABLE TO COMMON AND PREFERRED STOCK .............................. 100.0%++ $   211,784,795
                                                                                        ------   ---------------

MONEY MARKET CUMULATIVE PREFERRED(TM) STOCK (MMP(R)) REDEMPTION VALUE .........................      (70,000,000)
                                                                                                 ---------------
TOTAL NET ASSETS AVAILABLE TO COMMON STOCK ....................................................  $   141,784,795
                                                                                                 ===============


    The accompanying notes are an integral part of the financial statements.
                                       14



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                            PORTFOLIO OF INVESTMENTS (CONTINUED)
                                                        MAY 31, 2007 (UNAUDITED)
              ------------------------------------------------------------------

---------------------
*    Securities eligible for the Dividends Received Deduction and   distributing
     Qualified Dividend Income.
**   Securities distributing Qualified Dividend Income only.
***  Aggregate cost of securities held.
**** Securities exempt from  registration  under Rule 144A of the Securities Act
     of 1933. These  securities  may  be  resold  in  transactions  exempt  from
     registration to qualified  institutional buyers. These securities have been
     determined to be liquid under  the  guidelines  established by the Board of
     Directors.
(1)  Foreign Issuer.
(2)  All or a portion of this  security  has  been  pledged  as  collateral  for
     written options  positions.
+    Non-income  producing.
++   The percentage  shown for each investment  category is  the  total value of
     that  category  as  a  percentage  of  net  assets  available to Common and
     Preferred Stock.

          ABBREVIATIONS:
Pfd.   -- Preferred Securities
Pvt.   -- Private Placement Securities

OPEN OPTION CONTRACTS WRITTEN


CONTRACTS         CONTRACT DESCRIPTION                                                        VALUE
--------------    --------------------                                                    --------------
                                                                                 
         100      September Call Options on September U.S. Treasury Bond Futures,
                     Expiring 08/24/07, Strike Price 110 ...............................  $   (84,375)+
-----------------------------------------------------------------------------------------------------
                  TOTAL OPEN OPTION CONTRACTS WRITTEN (premiums received: $91,713) .....      (84,375)
                                                                                          -----------


    The accompanying notes are an integral part of the financial statements.
                                       15



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
STATEMENT OF ASSETS AND LIABILITIES
MAY 31, 2007 (UNAUDITED)
------------------------------------------------------------------



                                                                                         
ASSETS:
  Investments, at value (Cost $202,514,061) .........................                          $ 211,656,634
  Dividends and interest receivable .................................                              1,328,756
  Prepaid expenses ..................................................                                148,062
                                                                                               -------------
       Total Assets .................................................                            213,133,452
LIABILITIES:
  Payable for Investments purchased .................................  $ 500,000
  Dividends payable to Common Stock Shareholders ....................     87,282
  Investment advisory fee payable ...................................    101,788
  Administration, Transfer Agent and Custodian fees payable .........     32,024
  Professional fees payable .........................................     64,160
  Directors' fees payable ...........................................      3,030
  Accrued expenses and other payables ...............................     47,653
  Accumulated undeclared distributions to Money Market Cumulative
    Preferred(TM) Stock Shareholders ................................    428,345
  Outstanding options written, at value (premiums received $91,713) .     84,375
                                                                       ---------
       Total Liabilities ............................................                              1,348,657
                                                                                               -------------
MONEY MARKET CUMULATIVE PREFERRED(TM) STOCK (700 SHARES
  OUTSTANDING) REDEMPTION VALUE .....................................                             70,000,000
                                                                                               -------------
NET ASSETS AVAILABLE TO COMMON STOCK ................................                          $ 141,784,795
                                                                                               =============
NET ASSETS AVAILABLE TO COMMON STOCK consist of:
  Distributions in excess of net investment income ..................                          $    (237,871)
  Accumulated net realized loss on investments sold .................                             (2,847,206)
  Unrealized appreciation of investments ............................                              9,149,910
  Par value of Common Stock .........................................                                117,219
  Paid-in capital in excess of par value of Common Stock ............                            135,602,743
                                                                                               -------------
       Total Net Assets Available to Common Stock ...................                          $ 141,784,795
                                                                                               =============
NET ASSET VALUE PER SHARE OF COMMON STOCK:
  Common Stock (11,721,854 shares outstanding) ......................                          $       12.10
                                                                                               =============


    The accompanying notes are an integral part of the financial statements.
                                       16



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                                         STATEMENT OF OPERATIONS
                               FOR THE SIX MONTHS ENDED MAY 31, 2007 (UNAUDITED)
              ------------------------------------------------------------------



        
INVESTMENT INCOME:
   Dividends+ .....................................................                              $ 5,518,852
   Interest .......................................................                                1,750,397
                                                                                                 -----------
      Total Investment Income .....................................                                7,269,249
EXPENSES:
   Investment advisory fee ........................................  $   599,697
   Administrator's fee ............................................      104,645
   Money Market Cumulative Preferred(TM) Stock broker commissions
      and auction agent fees ......................................       91,972
   Professional fees ..............................................       66,976
   Insurance expense ..............................................       74,000
   Transfer agent fees ............................................       38,422
   Directors' fees ................................................       39,130
   Custodian fees .................................................       13,360
   Compliance fees ................................................       19,694
   Other ..........................................................       83,572
                                                                     -----------
      Total Expenses ..............................................                                1,131,468
                                                                                                 -----------
NET INVESTMENT INCOME .............................................                                6,137,781
                                                                                                 -----------
REALIZED AND UNREALIZED GAIN/(LOSS) ON INVESTMENTS
   Net realized gain/(loss) on investments sold during the period .                                 (794,075)
   Change in net unrealized appreciation/depreciation of investments
      held during the period ......................................                               (5,103,181)
                                                                                                 -----------
NET REALIZED AND UNREALIZED LOSS ON INVESTMENTS ...................                               (5,897,256)
                                                                                                 -----------
DISTRIBUTIONS TO MONEY MARKET CUMULATIVE PREFERRED(TM)
  STOCK SHAREHOLDERS:
   From net investment income (including changes in accumulated
      undeclared distributions) ...................................                               (1,576,114)
                                                                                                 -----------
NET DECREASE IN NET ASSETS TO COMMON STOCK RESULTING
  FROM OPERATIONS .................................................                              $(1,335,589)
                                                                                                 ===========

------------
+ For Federal income tax purposes, a significant portion of this amount  may not
  qualify  for  the inter-corporate  dividends received deduction ("DRD") or  as
  qualified dividend income ("QDI") for individuals.



    The accompanying notes are an integral part of the financial statements.
                                       17



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
STATEMENTS OF CHANGES IN NET ASSETS AVAILABLE TO COMMON STOCK(1)
---------------------------------------------------------------




                                                                                     SIX MONTHS ENDED
                                                                                       MAY 31, 2007                YEAR ENDED
                                                                                        (UNAUDITED)             NOVEMBER 30, 2006
                                                                                                          
OPERATIONS:
  Net investment income ........................................................   $    6,137,781               $   11,909,799
  Net realized gain/(loss) on investments sold during the period ...............         (794,075)                   3,470,490
  Change in net unrealized appreciation/depreciation of investments
    held during the period .....................................................       (5,103,181)                   2,218,263
  Distributions to MMP(R)* Shareholders from net investment income,
    including changes in accumulated undeclared distributions ..................       (1,576,114)                  (2,877,427)
                                                                                   --------------               --------------
  NET INCREASE/(DECREASE) IN NET ASSETS RESULTING FROM OPERATIONS ..............       (1,335,589)                  14,721,125
DISTRIBUTIONS:
  Dividends paid from net investment income to Common Stock
    Shareholders(1) ............................................................       (4,565,631)                  (9,312,018)
                                                                                   --------------               --------------
  TOTAL DISTRIBUTIONS TO COMMON STOCK SHAREHOLDERS .............................       (4,565,631)                  (9,312,018)
FUND SHARE TRANSACTIONS:
  Increase from shares issued under the Dividend Reinvestment
    and Cash Purchase Plan .....................................................          328,689                      231,696
                                                                                   --------------               --------------
  Net increase in net assets available to Common Stock
    resulting from Fund share transactions .....................................          328,689                      231,696
                                                                                   --------------               --------------

NET INCREASE/(DECREASE) IN NET ASSETS AVAILABLE TO                                 --------------               --------------
  COMMON STOCK FOR THE period ..................................................   $   (5,572,531)              $    5,640,803
                                                                                   ==============               ==============
------------------------------------------------------------------------------------------------------------------------------------
NET ASSETS AVAILABLE TO COMMON STOCK:
  Beginning of period ..........................................................   $  147,357,326               $  141,716,523
  Net increase/(decrease) in net assets during the period ......................       (5,572,531)                   5,640,803
                                                                                   --------------               --------------
  End of period (including distributions in excess of net investment
    income of ($237,871) and ($233,907), respectively) .........................   $  141,784,795               $  147,357,326
                                                                                   ==============               ==============

------------
   *    Money Market Cumulative PreferredTM Stock.
 (1)    May include income earned, but not paid out, in prior fiscal year.



    The accompanying notes are an integral part of the financial statements.
                                       18



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                                            FINANCIAL HIGHLIGHTS
                    FOR A COMMON STOCK SHARE OUTSTANDING THROUGHOUT EACH PERIOD.
              ------------------------------------------------------------------
Contained  below is per  share  operating  performance  data,  total  investment
returns,  ratios to  average  net  assets,  and other  supplemental  data.  This
information  has  been  derived  from  information  provided  in  the  financial
statements and market price data for the Fund's shares.




                                                                  SIX MONTHS
                                                                    ENDED                        YEAR ENDED NOVEMBER 30,
                                                                 MAY 31, 2007 ----------------------------------------------------
                                                                 (UNAUDITED)     2006       2005       2004      2003      2002
                                                               -------------- ---------   --------   -------   -------   --------
                                                                                                      
PER SHARE OPERATING PERFORMANCE:
Net asset value, beginning of year ..........................  $    12.60     $  12.14   $  12.27   $  12.59  $  10.78  $  11.60
                                                               ----------     --------   --------   --------  --------  --------
INVESTMENT OPERATIONS:
Net investment income .......................................        0.52         1.02       0.96       0.98      1.02      1.07
Net realized and unrealized gain/(loss) on investments ......       (0.50)        0.49      (0.01)     (0.27)     1.85     (0.87)
DISTRIBUTIONS TO MMP(R)* SHAREHOLDERS:
From net investment income ..................................       (0.13)       (0.25)     (0.17)     (0.09)    (0.08)    (0.11)
                                                               ----------     --------   --------   --------  --------  --------
Total from investment operations ............................       (0.11)        1.26       0.78       0.62      2.79      0.09
                                                               ----------     --------   --------   --------  --------  --------
DISTRIBUTIONS TO COMMON STOCK SHAREHOLDERS:
From net investment income ..................................       (0.39)       (0.80)     (0.91)     (0.94)    (0.98)    (0.91)
                                                               ----------     --------   --------   --------  --------  --------
Total distributions to Common Stock Shareholders ............       (0.39)       (0.80)     (0.91)     (0.94)    (0.98)    (0.91)
                                                               ----------     --------   --------   --------  --------  --------
Net asset value, end of year ................................  $    12.10     $  12.60   $  12.14   $  12.27  $  12.59  $  10.78
                                                               ==========     ========   ========   ========  ========  ========
Market value, end of year ...................................  $    12.13     $  12.42   $  11.53   $  13.53  $  13.51  $  11.72
                                                               ==========     ========   ========   ========  ========  ========
Total investment return based on net asset value** ..........      (0.90%)****  11.02%      6.36%      4.68%    26.57%     0.63%
                                                               ==========     ========   ========    =======  ========  ========
Total investment return based on market value** .............       0.79%****   15.22%     (8.40%)     7.57%    24.92%    12.61%
                                                               ==========     ========   ========   ========  ========  ========
RATIOS TO AVERAGE NET ASSETS AVAILABLE
  TO COMMON STOCK SHAREHOLDERS:
    Total net assets, end of year (in 000's) ................  $  141,785     $147,357   $141,717   $142,145  $144,303  $122,258
    Operating expenses ......................................        1.56%***     1.52%      1.53%      1.52%     1.54%     1.56%
    Net investment income + .................................        6.28%***     6.34%      6.30%      7.11%     7.85%     8.67%
-------------------------------------------------------------
SUPPLEMENTAL DATA:++
   Portfolio turnover rate ..................................          36%****      68%        57%        28%       28%       29%
   Total net assets available to Common and Preferred Stock,
     end of year (in 000's) .................................  $  211,785     $217,357   $211,717   $212,145  $214,411  $192,361
   Ratio of operating expenses to total average net assets
     available to Common and Preferred Stock ................        1.05%***     1.02%      1.03%      1.03%     1.02%     1.00%

   *   Money Market Cumulative Preferred(TM) Stock.
  **   Assumes  reinvestment of  distributions  at  the  price  obtained  by the
       Fund's Dividend Reinvestment and Cash Purchase Plan.
 ***   Annualized.
****   Not Annualized.
   +   The net  investment  income  ratios  reflect  income   net   of operating
       expenses and payments to MMP(R)* Shareholders.
  ++   Information presented under heading Supplemental Data includes MMP(R)*.



    The accompanying notes are an integral part of the financial statements.
                                       19



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Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
FINANCIAL HIGHLIGHTS (CONTINUED)
PER SHARE OF COMMON STOCK (UNAUDITED)
----------------------------------------------------------------



                                    TOTAL                                     DIVIDEND
                                  DIVIDENDS     NET ASSET        NYSE       REINVESTMENT
                                    PAID         VALUE      CLOSING PRICE      PRICE (1)
                                 ----------     ---------   -------------   ------------
                                                                   
December 31, 2006 ..............   $0.0650        $12.39        $12.36         $12.39
January 31, 2007 ...............    0.0650         12.42         12.39          12.42
February 28, 2007 ..............    0.0650         12.60         12.61          12.60
March 31, 2007 .................    0.0650         12.32         12.66          12.32
April 30, 2007 .................    0.0650         12.33         12.62          12.33
May 31, 2007 ...................    0.0650         12.10         12.13          12.10

(1)  Whenever  the net asset value per share of the Fund's  Common Stock is less
     than or  equal  to the  market  price per share on the  payment  date,  new
     shares issued  will be  valued  at the  higher  of net  asset  value or 95%
     of the then current  market  price. Otherwise, the  reinvestment  shares of
     Common Stock will be purchased in the open market.



    The accompanying notes are an integral part of the financial statements.
                                       20



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                                                FINANCIAL HIGHLIGHTS (CONTINUED)
              ------------------------------------------------------------------
         The table  below sets out  information  with  respect  to Money  Market
Cumulative Preferred(TM) Stock currently outstanding.




                                                         INVOLUNTARY           AVERAGE
                                         ASSET           LIQUIDATING            MARKET
                  TOTAL SHARES         COVERAGE          PREFERENCE             VALUE
   DATE         OUTSTANDING (1)     PER SHARE (2)       PER SHARE (3)      PER SHARE (1)(3)
---------       ---------------     -------------       -------------      ----------------
                                                                 
05/31/07*           700              $303,162             $100,000           $100,000
11/30/06            700               310,819              100,000            100,000
11/30/05            700               302,788              100,000            100,000
11/30/04            700               303,137              100,000            100,000
11/30/03            700               306,301              100,000            100,000
11/30/02            700               274,802              100,000            100,000

---------
(1) See note 6.
(2) Calculated by subtracting the Fund's total liabilities (excluding the MMP(R)
    and  accumulated   undeclared distributions to MMP(R)) from the Fund's total
    assets and  dividing that amount by the number of MMP(R) shares outstanding.
(3) Excludes accumulated undeclared dividends.
 *  Unaudited.



    The accompanying notes are an integral part of the financial statements.
                                       21



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Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
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1.   ORGANIZATION

     Flaherty & Crumrine  Preferred Income  Opportunity Fund  Incorporated  (the
"Fund") was  incorporated  as a Maryland  corporation  on December 10, 1991, and
commenced  operations  on  February  13,  1992  as  a  diversified,   closed-end
management  investment  company  under the  Investment  Company Act of 1940,  as
amended  (the "1940  Act").  The Fund's  investment  objective is to provide its
common shareholders with high current income consistent with the preservation of
capital.

2.   SIGNIFICANT ACCOUNTING POLICIES

     The following is a summary of significant  accounting policies consistently
followed  by the  Fund  in the  preparation  of its  financial  statements.  The
preparation of the financial statements is in conformity with the U.S. generally
accepted  accounting  principles  ("US GAAP") and  requires  management  to make
estimates  and  assumptions  that  affect  the  reported  amounts  of assets and
liabilities in the financial  statements  and the reported  amounts of increases
and decreases in net assets from operations during the reporting period.  Actual
results could differ from those estimates.

     PORTFOLIO  VALUATION:  The net asset  value of the Fund's  Common  Stock is
determined  by the  Fund's  Administrator  no less  frequently  than on the last
business day of each week and month.  It is  determined by dividing the value of
the  Fund's  net  assets  available  to Common  Stock by the number of shares of
Common Stock  outstanding.  The value of the Fund's net assets  attributable  to
Common  Stock is deemed to equal the value of the Fund's  total  assets less (i)
the  Fund's  liabilities  and  (ii)  the  aggregate  liquidation  value  of  the
outstanding Money Market Cumulative Preferred(TM) Stock ("MMP(R)").

     The Fund's preferred and debt securities are valued on the basis of current
market quotations  provided by independent  pricing services or dealers approved
by the Board of  Directors of the Fund.  Each  quotation is based on the mean of
the bid and asked prices of a security. In determining the value of a particular
preferred or debt security, a pricing service or dealer may use information with
respect to transactions in such investments,  quotations, market transactions in
comparable  investments,  various  relationships  observed in the market between
investments,  and/or  calculated  yield measures  based on valuation  technology
commonly  employed in the market for such  investments.  Common  stocks that are
traded on stock  exchanges  are valued at the last sale price or official  close
price on the exchange, as of the close of business on the day the securities are
being valued or, lacking any sales,  at the last  available mean price.  Futures
contracts and option  contracts on futures  contracts are valued on the basis of
the settlement  price for such  contracts on the primary  exchange on which they
trade. Investments in over-the-counter derivative instruments,  such as interest
rate swaps and options thereon  ("swaptions"),  are valued using prices supplied
by a pricing service,  or if such prices are  unavailable,  prices provided by a
single broker or dealer that is not the  counterparty  or, if no such prices are
available, at a price at which the counterparty to the contract would repurchase
the  instrument  or  terminate  the  contract.   Investments  for  which  market
quotations are not readily available or for which management determines that the
prices are not reflective of current market  conditions are valued at fair value
as  determined in good faith by or under the direction of the Board of Directors
of the Fund,  including  reference to valuations of other  securities  which are
comparable  in  quality,   maturity  and  type.   Investments  in  money  market
instruments  and all debt and  preferred  securities  which mature in 60 days or
less are valued at amortized cost.

                                       22



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              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                           NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)
              ------------------------------------------------------------------

Investments in money market funds are valued at the net asset value of such
funds.

     SECURITIES TRANSACTIONS AND INVESTMENT INCOME:  Securities transactions are
recorded as of the trade date.  Realized gains and losses from  securities  sold
are  recorded  on the  identified  cost  basis.  Dividend  income is recorded on
ex-dividend  dates.  Interest income is recorded on the accrual basis.  The Fund
also amortizes premiums and accretes discounts on fixed income securities.

     OPTIONS:  Purchases of options are recorded as an investment,  the value of
which is  marked-to-market  at each valuation  date. When the Fund enters into a
closing sale  transaction,  the Fund will record a gain or loss depending on the
difference  between the  purchase  and sale  price.  The risks  associated  with
purchasing  options and the maximum loss the Fund would incur are limited to the
purchase price originally paid.

     When the Fund writes an option,  an amount equal to the premium received by
the Fund is recorded as a liability,  the value of which is  marked-to-market at
each valuation  date.  When a written option  expires,  the Fund realizes a gain
equal to the amount of the  premium  originally  received.  When the Fund enters
into a closing  purchase  transaction,  the Fund realizes a gain (or loss if the
cost of the closing purchase  transaction  exceeds the premium received when the
option  was  written)  without  regard  to any  unrealized  gain  or loss on the
underlying  security,  and the liability  related to such option is  eliminated.
When a call option is exercised,  the Fund realizes a gain or loss from the sale
of the underlying  security and the proceeds from such sale are increased by the
amount of the premium originally received.  When a put option is exercised,  the
amount of the premium  originally  received will reduce the cost of the security
which the Fund purchased upon exercise.

     The  risk in  writing  a call  option  is that  the  Fund  may  forego  the
opportunity for profit if the market price of the underlying  security increases
and the option is  exercised.  The risk in writing a put option is that the Fund
may incur a loss if the market price of the  underlying  security  decreases and
the option is exercised.

     REPURCHASE  AGREEMENTS:   The  Fund  may  engage  in  repurchase  agreement
transactions. The Fund's investment adviser reviews and approves the eligibility
of the banks and dealers with which the Fund may enter into repurchase agreement
transactions.  The value of the collateral  underlying  such  transactions is at
least  equal at all times to the total  amount  of the  repurchase  obligations,
including interest.  The Fund maintains possession of the collateral through its
custodian and, in the event of counterparty  default,  the Fund has the right to
use the collateral to offset losses  incurred.  There is the possibility of loss
to the Fund in the event the Fund is delayed or prevented  from  exercising  its
rights to dispose of the collateral securities.

     FEDERAL  INCOME  TAXES:  The Fund  intends  to  continue  to  qualify  as a
regulated investment company by complying with the requirements under subchapter
M of the Internal  Revenue  Code of 1986,  as amended,  applicable  to regulated
investment companies and intends to distribute  substantially all of its taxable
net  investment  income to its  shareholders.  Therefore,  no federal income tax
provision is required.

     DIVIDENDS AND  DISTRIBUTIONS TO  SHAREHOLDERS:  The Fund expects to declare
dividends on a monthly

                                       23



--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)
------------------------------------------------------------------

basis  to  shareholders  of   Common Stock  ("Shareholders").  Distributions  to
Shareholders are recorded on the ex-dividend  date. Any net realized  short-term
capital gains will be distributed to  Shareholders  at least  annually.  Any net
realized  long-term  capital gains may be distributed to  Shareholders  at least
annually  or may be retained by the Fund as  determined  by the Fund's  Board of
Directors.  Capital gains retained by the Fund are subject to tax at the capital
gains  corporate  tax  rate.  Subject  to the  Fund  qualifying  as a  regulated
investment  company,  any taxes paid by the Fund on such net realized  long-term
capital gains may be used by the Fund's  Shareholders  as a credit against their
own tax liabilities.

     Income and capital gain  distributions  are determined and characterized in
accordance  with income tax  regulations  which may differ  from US GAAP.  These
differences are primarily due to (1) differing treatments of income and gains on
various investment  securities held by the Fund,  including timing  differences,
(2) the attribution of expenses against certain components of taxable investment
income, and (3) federal regulations requiring proportionate allocation of income
and gains to all classes of shareholders.

     Distributions  from net  realized  gains  for  book  purposes  may  include
short-term  capital  gains,  which  are  included  as  ordinary  income  for tax
purposes,  and may  exclude  amortization  of premium on  certain  fixed  income
securities, which are not reflected in ordinary income for tax purposes. The tax
character of distributions  paid,  including  changes in accumulated  undeclared
distributions to MMP(R) Shareholders, during 2007 and 2006 was as follows:



                   DISTRIBUTIONS  PAID IN FISCAL  YEAR 2007         DISTRIBUTIONS  PAID IN FISCAL YEAR 2006
                 ORDINARY  INCOME  LONG-TERM CAPITAL GAINS        ORDINARY  INCOME   LONG-TERM CAPITAL GAINS
                                                                                   
Common                   N/A               N/A                      $9,312,018                 $0
Preferred                N/A               N/A                      $2,877,427                 $0


As of November  30,  2006,  the  components  of  distributable  earnings  (i.e.,
ordinary income and capital  gain/loss)  available to Common and Preferred Stock
Shareholders, on a tax basis, were as follows:



                                    UNDISTRIBUTED            UNDISTRIBUTED            NET UNREALIZED
CAPITAL (LOSS) CARRYFORWARD        ORDINARY INCOME          LONG-TERM GAIN     APPRECIATION/(DEPRECIATION)
                                                                            
     ($1,918,273)                     $321,816                   $0                  $14,118,233


     At November 30, 2006, the composition of the Fund's $1,918,273  accumulated
realized   capital  losses  was  $1,223,987  and  $694,286  in  2002  and  2004,
respectively.  These losses may be carried forward and offset against any future
capital gains through 2010 and 2012, respectively.

     EXCISE TAX: The Internal  Revenue  Code of 1986,  as amended,  imposes a 4%
nondeductible  excise tax on the Fund to the extent the Fund does not distribute
by the  end of  any  calendar  year  at  least  (1)  98% of the  sum of its  net
investment income for that year and its capital gains (both long-term and short-
term) for its fiscal year and (2) certain  undistributed  amounts from  previous
years.  The Fund paid $31,373 of Federal excise taxes  attributable  to calendar
year 2006 in March 2007.

     ADDITIONAL  ACCOUNTING  STANDARDS:  In June 2006, the Financial  Accounting
Standards Board ("FASB")

                                       24



--------------------------------------------------------------------------------
              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                           NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)
              ------------------------------------------------------------------

issued FASB  Interpretation 48 ("FIN 48"), "Accounting for Uncertainty in Income
Taxes." This  standard  defines the  threshold  for recognizing the benefits  of
tax-return positions in the financial statements as "more-likely-than-not" to be
sustained  by the taxing  authority  and requires measurement of a tax  position
meeting the more-likely-than-not  criterion, based on the largest  benefit  that
is more than 50 percent likely to be realized.  FIN 48 is effective as   of  the
beginning  of the first fiscal year  beginning  after December  15, 2006,   with
early application permitted if no interim financial statements have been issued.
At adoption,  companies must adjust their financial statements to reflect   only
those tax positions that are more likely- than-not to be sustained   as  of  the
adoption date.

     In addition, in September 2006, Statement of Financial Accounting Standards
No. 157 FAIR VALUE  MEASUREMENTS  ("SFAS 157") was issued and is  effective  for
fiscal years  beginning  after  November 15, 2007.  SFAS 157 defines fair value,
establishes a framework for measuring fair value and expands  disclosures  about
fair value measurements.

     Management  is currently  evaluating  the impact the adoption of FIN 48 and
SFAS 157 will have on the Fund's financial statements.

3.   INVESTMENT  ADVISORY FEE, ADMINISTRATION FEE, TRANSFER AGENT FEE, CUSTODIAN
     FEE, DIRECTORS' FEES AND CHIEF COMPLIANCE  OFFICER FEE

     Flaherty  &  Crumrine  Incorporated  (the  "Adviser")  serves as the Fund's
investment adviser. The Fund pays the Adviser a monthly fee at an annual rate of
0.625% of the value of the Fund's average monthly total net assets  available to
Common  and  Preferred  Stock up to $100  million  and 0.50% of the value of the
Fund's average monthly total net assets  available to Common and Preferred Stock
in excess of $100 million.

     For purposes of calculating the fees payable to the Adviser,  Administrator
and  Custodian,  the Fund's  average weekly total managed assets means the total
assets  of the Fund  minus  the sum of  accrued  liabilities.  For  purposes  of
determining  total managed assets,  the liquidation  preference of any preferred
shares issued by the Fund is not treated as a liability.

     PFPC  Inc.,  a member  of the PNC  Financial  Services  Group,  Inc.  ("PNC
Financial Services"), serves as the Fund's Administrator. As Administrator, PFPC
Inc.  calculates the net asset value of the Fund's shares attributable to Common
Stock and  generally  assists in all  aspects of the Fund's  administration  and
operation.  As compensation for PFPC Inc.'s services as Administrator,  the Fund
pays  PFPC  Inc.  a monthly  fee at an  annual  rate of 0.10% of the first  $200
million of the Fund's  average  weekly total managed  assets,  0.04% of the next
$300 million of the Fund's  average  weekly total managed  assets,  0.03% of the
next $500 million of the Fund's average weekly total managed assets and 0.02% on
the Fund's average weekly total managed assets above $1 billion.

     PFPC Inc. also serves as the Fund's Common Stock  dividend-paying agent and
registrar  (Transfer Agent). As compensation for PFPC Inc.'s services,  the Fund
pays PFPC Inc. a fee at an annual rate of 0.02% of the first $150 million of the
Fund's average weekly net assets  attributable  to Common Stock,  0.0075% of the
next $350 million of the Fund's average weekly net assets attributable to Common
Stock,  and  0.0025% of the Fund's  average  weekly net assets  attributable  to
Common Stock above $500 million,

                                       25


--------------------------------------------------------------------------------
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)
------------------------------------------------------------------

plus certain out of pocket  expenses.  For the purpose of calculating  such fee,
the  Fund's  average weekly net assets attributable  to Common  Stock are deemed
to be the average  weekly value of the Fund's total assets  minus the sum of the
Fund's  liabilities. For this calculation, the Fund's liabilities are deemed  to
include  the  aggregate liquidation preference of any outstanding Fund preferred
shares.

     PFPC Trust Company  ("PFPC  Trust")  serves as the Fund's  custodian.  PFPC
Trust is an indirect subsidiary of PNC Financial  Services.  As compensation for
PFPC Trust's  services as  custodian,  the Fund pays PFPC Trust a monthly fee at
the annual rate of 0.010% of the first $200 million of the Fund's average weekly
total  managed  assets,  0.008% of the next $300  million of the Fund's  average
weekly  total  managed  assets,  0.006% of the next $500  million  of the Fund's
average  weekly total  managed  assets and 0.005% of the Fund's  average  weekly
total managed assets above $1 billion.

     The Fund  currently  pays each  Director who is not a director,  officer or
employee of the Adviser a fee of $9,000 per annum,  plus $500 for each in-person
meeting of the Board of Directors or any committee  and $150 for each  telephone
meeting.  The Audit  Committee  Chairman  receives an  additional  annual fee of
$2,500.  The Fund also  reimburses  all Directors  for travel and  out-of-pocket
expenses incurred in connection with such meetings.

     The Fund  currently  pays the  Adviser a fee of $37,500 per annum for Chief
Compliance  Officer services and reimburses  out-of-pocket  expenses incurred in
connection  with  providing  services in this role.

4.   PURCHASES AND SALES OF SECURITIES

     For the six months ended May 31, 2007,  the cost of purchases  and proceeds
from  sales  of  securities   excluding   short-term   investments,   aggregated
$77,720,422 and $77,400,119, respectively.

     At May 31, 2007,  the aggregate  cost of securities  for federal income tax
purposes was $202,648,919,  the aggregate gross unrealized  appreciation for all
securities  in which  there is an excess of value over tax cost was  $10,977,683
and the aggregate  gross  unrealized  depreciation  for all  securities in which
there is an excess of tax cost over value was $1,969,968.

     Written  option transactions  during  the six  months  ended May 31,  2007,
are  summarized  as follows:



                                                        CONTRACT             PREMIUMS
                                                        AMOUNTS             RECEIVED
                                                    ----------------------------------
                                                                      
Written options outstanding at beginning of year ...          0             $      0
--------------------------------------------------------------------------------------
Options Opened .....................................        100               91,713
Options Exercised ..................................          0                    0
Options Expired ....................................          0                    0
Options Closed .....................................          0                    0
--------------------------------------------------------------------------------------
Written options outstanding at end of period .......        100             $ 91,713


                                       26



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              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
                           NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)
              ------------------------------------------------------------------

5.   COMMON STOCK

     At May 31,  2007,  240,000,000  shares of $0.01 par value Common Stock were
authorized. Common Stock transactions were as follows:



                                                          SIX MONTHS ENDED         YEAR ENDED
                                                              05/31/07              11/30/06
                                                          ----------------      -----------------
                                                           SHARES   AMOUNT       SHARES    AMOUNT
                                                          -------   ------      -------    ------
                                                                               
Shares issued under the Dividend Reinvestment and
  Cash Purchase Plan .................................... 26,482    $ 328,689   18,787     $ 231,696
                                                          ------    ---------   ------     ---------


6.   MONEY MARKET CUMULATIVE PREFERRED(TM) STOCK (MMP(R))

     The Fund's  Articles  of  Incorporation  authorize  the  issuance  of up to
10,000,000  shares of $0.01 par value preferred  stock.  The MMP(R) is senior to
the Common Stock and results in the  financial  leveraging  of the Common Stock.
Such  leveraging  tends to magnify  both the risks and  opportunities  to Common
Stock Shareholders. Dividends on shares of MMP(R) are cumulative.

     The Fund is required to meet certain asset  coverage  tests with respect to
the MMP(R).  If the Fund fails to meet these  requirements  and does not correct
such failure,  the Fund may be required to redeem, in part or in full, MMP(R) at
a redemption price of $100,000 per share plus an amount equal to the accumulated
and  unpaid  dividends  on such  shares  in  order to meet  these  requirements.
Additionally,  failure to meet the foregoing asset  requirements  could restrict
the Fund's ability to pay dividends to Common Stock  Shareholders and could lead
to sales of portfolio securities at inopportune times.

     If the Fund allocates any net gains or income  ineligible for the Dividends
Received  Deduction  to  shares  of the  MMP(R),  the Fund is  required  to make
additional distributions to MMP(R) Shareholders or to pay a higher dividend rate
in amounts needed to provide a return,  net of tax, equal to the return had such
originally  paid   distributions   been  eligible  for  the  Dividends  Received
Deduction.

     An auction of the MMP(R) is generally held every 49 days.  Existing  MMP(R)
Shareholders  may submit an order to hold,  bid or sell such shares at par value
on each auction date. MMP(R) Shareholders may also trade shares in the secondary
market, if any, between auction dates.

     At May 31, 2007,  700 shares of MMP(R) were  outstanding  at the annualized
rate of 4.04%.  The dividend rate, as set by the auction  process,  is generally
expected  to vary with  short-term  interest  rates.  These  rates may vary in a
manner  unrelated to the income received on the Fund's assets,  which could have
either a beneficial or  detrimental  impact on net  investment  income and gains
available to Common Stock Shareholders.  While the Fund expects to structure its
portfolio holdings and hedging transactions to lessen such risks to Common Stock
Shareholders, there can be no assurance that such results will be attained.

                                       27



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Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)
------------------------------------------------------------------

7.   PORTFOLIO INVESTMENTS, CONCENTRATION AND INVESTMENT QUALITY

     The  Fund  invests  primarily  in  a  diversified  portfolio  of  preferred
securities.   This  includes  traditional  preferred  stocks  eligible  for  the
inter-corporate dividends received deduction ("DRD") and fully taxable preferred
securities.  Under normal  market  conditions,  at least 80% of the value of the
Fund's net assets will be invested in preferred  securities.  Also, under normal
market  conditions,  the Fund  invests at least 25% of its assets in  securities
issued by companies in the utility industry and a significant percentage, but no
more than 25% of its assets,  in  securities  issued by companies in the banking
industry.  The Fund's  portfolio  may  therefore  be subject to greater risk and
market  fluctuation than a portfolio of securities  representing a broader range
of investment alternatives.

     The Fund may  invest  up to 25% of its  assets at the time of  purchase  in
securities rated below investment grade. These securities must be rated at least
either "Ba3" by Moody's  Investors  Service,  Inc. or "BB-" by Standard & Poor's
or, if unrated,  judged to be comparable in quality by the Adviser, in any case,
at the time of purchase.  However,  these securities must be issued by an issuer
having a class of senior debt rated investment grade outstanding.

     The Fund may invest up to 15% of its  assets in common  stocks  and,  under
normal market conditions, up to 20% of its assets in debt securities. Certain of
its investments in hybrid,  i.e.,  fully taxable,  preferred  securities will be
subject to the  foregoing  20%  limitation to the extent that, in the opinion of
the Adviser, such investments are deemed to be debt-like in key characteristics.
Typically,  a security  will not be  considered  debt-like  (a) if an issuer can
defer payment of income for eighteen months or more without  triggering an event
of default and (b) if such issue is a junior and fully subordinated liability of
an issuer or its ultimate guarantor.

     In addition to foreign money market  securities,  the Fund may invest up to
30% of its total assets in the securities of companies organized or having their
principal place of business  outside the United States.  All foreign  securities
held by the Fund will be denominated in U.S. dollars.

8.   SPECIAL INVESTMENT TECHNIQUES

     The Fund may employ certain  investment  techniques in accordance  with its
fundamental  investment  policies.  These may include the use of when-issued and
delayed delivery transactions.  Securities purchased or sold on a when-issued or
delayed  delivery  basis may be  settled  within  45 days  after the date of the
transaction.  Such  transactions  may  expose  the  Fund to  credit  and  market
valuation  risk  greater than that  associated  with  regular  trade  settlement
procedures.  The Fund may also enter into  transactions,  in accordance with its
investment  policies,  involving  any or all of the  following:  short  sales of
securities,  futures  contracts,  interest rate swaps, swap futures,  options on
futures  contracts,   options  on  securities,   swaptions  and  certain  credit
derivative transactions, including, but not limited to, the purchase and sale of
credit  protection.  As in  the  case  of  when-issued  securities,  the  use of
over-the-counter derivatives, such as interest rate swaps, swaptions, and credit
default swaps may expose the Fund to greater credit, operations,  liquidity, and
valuation  risk than is the case with  regulated,  exchange  traded  futures and
options.   These   transactions  are  used  for  hedging  or  other  appropriate
risk-management  purposes,  or, under certain other  circumstances,  to increase
return. No assurance can be

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              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
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given that such transactions will achieve  their desired purposes or will result
in an overall reduction of risk to the Fund.

9.   SECURITIES LENDING

     The Fund may lend up to 15% of its total assets (including the value of the
loan  collateral)  to  certain  qualified  brokers  in order to earn  additional
income. The Fund receives compensation in the form of fees or interest earned on
the  investment  of any cash  collateral  received.  The Fund also  continues to
receive  interest and  dividends on the  securities  loaned.  The Fund  receives
collateral in the form of cash or securities  with a market value at least equal
to the market value of the securities on loan,  including accrued  interest.  In
the event of default or bankruptcy by the  borrower,  the Fund could  experience
delays and costs in recovering the loaned securities or in gaining access to the
collateral.  The Fund has the right under the lending  agreement  to recover the
securities from the borrower on demand.

                                       29



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DIVIDEND REINVESTMENT AND CASH PURCHASE PLAN

     Under the Fund's Dividend Reinvestment and Cash Purchase Plan (the "Plan"),
a  shareholder  whose Common Stock is registered in their own name will have all
distributions  reinvested  automatically  by PFPC Inc.  as agent under the Plan,
unless the  shareholder  elects to receive cash.  Distributions  with respect to
shares  registered in the name of a broker-dealer  or other nominee (that is, in
"street  name") may be reinvested by the broker or nominee in additional  shares
under the Plan,  but only if the  service is  provided by the broker or nominee,
unless the shareholder  elects to receive  distributions  in cash. A shareholder
who holds Common Stock  registered  in the name of a broker or other nominee may
not be able to  transfer  the  Common  Stock to another  broker or  nominee  and
continue to participate in the Plan.  Investors who own Common Stock  registered
in street  name should  consult  their  broker or nominee for details  regarding
reinvestment.

     The number of shares of Common Stock  distributed  to  participants  in the
Plan in lieu of a cash dividend is determined in the following manner.  Whenever
the market price per share of the Fund's Common Stock is equal to or exceeds the
net asset value per share on the valuation  date,  participants in the Plan will
be issued new shares  valued at the higher of net asset value or 95% of the then
current market value. Otherwise,  PFPC Inc. will buy shares of the Fund's Common
Stock in the open market,  on the New York Stock Exchange ("NYSE") or elsewhere,
on or  shortly  after the  payment  date of the  dividend  or  distribution  and
continuing until the ex-dividend date of the Fund's next distribution to holders
of the Common Stock or until it has expended for such  purchases all of the cash
that would  otherwise  be payable to the  participants.  The number of purchased
shares that will then be credited to the participants' accounts will be based on
the  average  per share  purchase  price of the shares so  purchased,  including
brokerage  commissions.  If PFPC Inc. commences purchases in the open market and
the then  current  market  price of the  shares  (plus any  estimated  brokerage
commissions) subsequently exceeds their net asset value most recently determined
before the  completion  of the  purchases,  PFPC Inc.  will attempt to terminate
purchases in the open market and cause the Fund to issue the remaining  dividend
or  distribution  in shares.  In this case, the number of shares received by the
participant  will be based on the  weighted  average  of prices  paid for shares
purchased  in the  open  market  and the  price at which  the  Fund  issues  the
remaining  shares.  These  remaining  shares  will be  issued by the Fund at the
higher of net asset value or 95% of the then current market value.

     Plan  participants are not subject to any charge for reinvesting  dividends
or capital gains  distributions.  Each Plan participant  will,  however,  bear a
proportionate  share of  brokerage  commissions  incurred  with  respect to PFPC
Inc.'s open market purchases in connection with the reinvestment of dividends or
capital gains  distributions.  For the six months ended May 31, 2007, $291.36 in
brokerage commissions were incurred.

     The automatic  reinvestment  of dividends  and capital gains  distributions
will not relieve Plan  participants of any income tax that may be payable on the
dividends or capital  gains  distributions.  A  participant  in the Plan will be
treated for Federal  income tax  purposes as having  received,  on the  dividend
payment date, a dividend or distribution in an amount equal to the cash that the
participant could have received instead of shares.

                                       30



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              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
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     In addition to acquiring shares of Common Stock through the reinvestment of
cash dividends and  distributions,  a shareholder may invest any further amounts
from $100 to $3,000  semi-annually  at the then  current  market price in shares
purchased  through the Plan.  Such  semi-annual  investments  are subject to any
brokerage commission charges incurred by PFPC Inc. under the Plan.

     A  shareholder  whose Common Stock is registered in his or her own name may
terminate  participation  in the  Plan at any time by  notifying  PFPC  Inc.  in
writing,  by completing  the form on the back of the Plan account  statement and
forwarding it to PFPC Inc., or by calling PFPC Inc. directly. A termination will
be  effective  immediately  if notice is received by PFPC Inc.  not less than 10
days before any dividend or distribution record date. Otherwise, the termination
will be  effective,  and  only  with  respect  to any  subsequent  dividends  or
distributions,  on the first day after the  dividend  or  distribution  has been
credited to the  participant's  account in additional  shares of the Fund.  Upon
termination and according to a participant's instructions, PFPC Inc. will either
(a) issue  certificates for the whole shares credited to the shareholder's  Plan
account and a check representing any fractional shares or (b) sell the shares in
the market.  Shareholders  who hold  Common  Stock  registered  in the name of a
broker or other  nominee  should  consult  their  broker or nominee to terminate
participation.

     The  Plan  is  described  in  more  detail  in the  Fund's  Plan  brochure.
Information   concerning   the  Plan  may  be   obtained   from  PFPC  Inc.   at
1-800-331-1710.

PROXY VOTING POLICIES AND PROXY VOTING RECORD ON FORM N-PX

     The Fund files Form N-PX with its complete  proxy voting  record for the 12
months  ended June 30th no later than August  31st of each year.  The Fund filed
its latest Form N-PX with the  Securities  and  Exchange  Commission  ("SEC") on
August 16, 2006.  This filing,  as well as the Fund's proxy voting  policies and
procedures,  are available  (i) without  charge,  upon  request,  by calling the
Fund's  transfer  agent at  1-800-331-1710  and  (ii) on the  SEC's  website  at
WWW.SEC.GOV.  In addition,  the Fund's proxy voting  policies and procedures are
available on the Fund's website at WWW.PREFERREDINCOME.COM.

PORTFOLIO SCHEDULE ON FORM N-Q

     The Fund files a complete  schedule of portfolio  holdings with the SEC for
the first and third  fiscal  quarters on Form N-Q, the latest of which was filed
for the quarter ended February 28, 2007. The Fund's Form N-Q is available on the
SEC's website at WWW.SEC.GOV or may be viewed and obtained from the SEC's Public
Reference  Room in Washington  D.C.  Information  on the operation of the Public
Reference Section may be obtained by calling 1-800-SEC-0330.

PORTFOLIO MANAGEMENT TEAM

     In managing the  day-to-day  operations of the Fund,  the Adviser relies on
the  expertise  of its team of money  management  professionals,  consisting  of
Messrs. Crumrine,  Ettinger, Stone and Chadwick. The professional backgrounds of
each member of the management team are included in the  "Information  about Fund
Directors and Officers" section of this report.

                                       31



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CERTIFICATIONS

     Included in the Annual Written Affirmation submitted to the NYSE, Donald F.
Crumrine,  as the Fund's Chief Executive Officer,  has certified that, as of May
16,  2007,  he was not aware of any  violation  by the Fund of  applicable  NYSE
corporate  governance listing standards.  The Fund's reports to the SEC on Forms
N-CSR and N-Q contain  certifications by the Fund's principal  executive officer
and  principal  financial  officer that relate to the Fund's  disclosure in such
reports and that are required by Rule  30a-2(a)  under the 1940 Act.

MEETING OF SHAREHOLDERS

     On April 20, 2007,  the Fund held its Annual Meeting of  Shareholders  (the
"Meeting")  for  the  following  purpose:  election  of  Directors  of the  Fund
("Proposal 1"). The proposal was approved by the shareholders and the results of
the voting are as follows:

PROPOSAL 1: ELECTION OF DIRECTORS

NAME                                                         FOR        WITHHELD

COMMON  STOCK
Robert F.  Wulf ........................................ 10,812,258      126,748

PREFERRED  STOCK
Donald F. Crumrine .....................................        510            0

     David  Gale,  Morgan  Gust and Karen H.  Hogan  continue  to serve in their
capacities as Directors of the Fund.

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              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
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INFORMATION ABOUT FUND DIRECTORS AND OFFICERS

         The business and affairs of the Fund are managed under the direction of
the Fund's Board of  Directors.  Information  pertaining  to the  Directors  and
officers of the Fund is set forth below.




                                                                      PRINCIPAL         NUMBER OF FUNDS
                                              TERM OF OFFICE        OCCUPATION(S)       IN FUND COMPLEX
NAME, ADDRESS,              POSITION(S)        AND LENGTH OF         DURING PAST           OVERSEEN             OTHER DIRECTORSHIPS
AND  AGE                  HELD WITH FUND       TIME SERVED*          FIVE YEARS           BY DIRECTOR             HELD BY DIRECTOR
                                                                                            
NON-INTERESTED
DIRECTORS:

DAVID GALE                  Director           Class I Director    President & CEO of         4            Metromedia International
Delta Dividend Group, Inc.                    since January 1997   Delta Dividend                          Group, Inc.
220 Montgomery Street                                              Group, Inc. (investments)               (telecommunications);
Suite 426                                                                                                  Flaherty & Crumrine
San Francisco, CA 94104                                                                                    Preferred Income Fund;
Age: 58                                                                                                    Flaherty & Crumrine/
                                                                                                           Claymore Preferred
                                                                                                           Securities Income Fund;
                                                                                                           and Flaherty &
                                                                                                           Crumrine/Claymore
                                                                                                           Total Return Fund

MORGAN GUST                 Director           Class III Director  Retired; Former            4            CoBiz, Inc. (financial
301 E. Colorado Boulevard                     since January 1991   President of Giant                      services); Flaherty &
Suite 720                                                          Industries, Inc. (petroleum             Crumrine Preferred
Pasadena, CA 91101                                                 refining and marketing)                 Income Opportunity
Age: 60                                                            since March 2002                        Fund; Flaherty &
                                                                                                           Crumrine/Claymore
                                                                                                           Preferred Securities
                                                                                                           Income Fund; and
                                                                                                           Flaherty & Crumrine/
                                                                                                           Claymore Total Return
                                                                                                           Fund

------------------------
* The Fund's Board of Directors is divided into three classes, each class having
  a  term  of three years. Each year the term of office of one class expires and
  the successor or successors elected to such class serve for a three year term.
  The three year term for each class expires as follows:

                            CLASS I DIRECTOR - three year term expires at the Fund's 2009 Annual  Meeting of
                            Shareholders;  director  may  continue  in office  until his  successor  is duly
                            elected  and  qualified.
                            CLASS II  DIRECTORS  - three year term  expires at the Fund's 2010 Annual Meeting
                            of  Shareholders;  directors  may continue in office until their successors are
                            duly elected and qualified.
                            CLASS III DIRECTORS - three year term expires at the Fund's 2008 Annual  Meeting
                            of  Shareholders;  directors may continue in office until their  successors  are
                            duly elected and qualified.



                                       33



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Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
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                                                                      PRINCIPAL         NUMBER OF FUNDS
                                              TERM OF OFFICE        OCCUPATION(S)       IN FUND COMPLEX
NAME, ADDRESS,              POSITION(S)        AND LENGTH OF         DURING PAST           OVERSEEN             OTHER DIRECTORSHIPS
AND  AGE                  HELD WITH FUND       TIME SERVED*          FIVE YEARS           BY DIRECTOR             HELD BY DIRECTOR
                                                                                            
NON-INTERESTED
DIRECTORS:

KAREN H. HOGAN+             Director           Class III Director  Retired; Community         4            Flaherty & Crumrine
301 E. Colorado Boulevard                       since April 2005   Volunteer; from September               Preferred Income Fund;
Suite 720                                                          1985 to January 1997,                   Flaherty & Crumrine/
Pasadena, CA 91101                                                 Senior Vice President of                Claymore Preferred
Age: 46                                                            Preferred Stock Origination             Securities Income Fund;
                                                                   at Lehman Brothers and                  and Flaherty & Crumrine/
                                                                   previously, Vice President of           Claymore Total Return
                                                                   New Product Development                 Fund

ROBERT F. WULF              Director           Class II Director   Financial Consultant;      4            Flaherty & Crumrine
P.O. Box 753                                  since February 1992  Trustee, University of                  Preferred Income Fund;
Neskowin, Oregon 97149                                             Oregon Foundation;                      Flaherty & Crumrine/
Age: 70                                                            Trustee, San Francisco                  Claymore Preferred
                                                                   Theological Seminary                    Securities Income Fund;
                                                                                                           and Flaherty &
                                                                                                           Crumrine/Claymore
                                                                                                           Total Return Fund
INTERESTED
DIRECTOR:

DONALD F. CRUMRINE+, ++     Director,          Class II Director   Chairman of the Board      4            Flaherty & Crumrine
301 E. Colorado Boulevard   Chairman         since February 1992   and Director of Flaherty &              Preferred Income Fund;
Suite 720                 of the Board                             Crumrine Incorporated                   Flaherty & Crumrine/
Pasadena, CA 91101         and Chief                                                                       Claymore Preferred
Age: 59                 Executive Officer                                                                  Securities Income Fund;
                                                                                                           and Flaherty &
                                                                                                           Crumrine/Claymore
                                                                                                           Total Return Fund

*  The  Fund's  Board  of  Directors  is  divided into three classes, each class
   having a term  of  three   years. Each year the term of office of  one  class
   expires and the successor or successors  elected  to  such class serve for  a
   three year term. The three year term for each class expires as follows:

                            CLASS I DIRECTOR - three year term expires at the Fund's 2009 Annual  Meeting of
                            Shareholders;  director  may  continue  in office  until his  successor  is duly
                            elected  and  qualified.
                            CLASS II  DIRECTORS  - three year term  expires at the Fund's 2010 Annual Meeting
                            of  Shareholders;  directors  may continue in office until their successors are
                            duly elected and qualified.
                            CLASS III DIRECTORS - three year term expires at the Fund's 2008 Annual  Meeting
                            of  Shareholders;  directors may continue in office until their  successors  are
                            duly elected and qualified.

+  As  a   Director,  represents  holders  of the Fund's Money Market Cumulative
   Preferred(TM) Stock.
++ "Interested person" of the Fund as defined in  the Investment  Company Act of
   1940, as amended.  Mr.  Crumrine is considered an "interested person" because
   of his  affiliation  with Flaherty & Crumrine Incorporated which, acts as the
   Fund's investment adviser.



                                       34



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              Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
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                                                                      PRINCIPAL
                                              TERM OF OFFICE        OCCUPATION(S)
NAME, ADDRESS,              POSITION(S)        AND LENGTH OF         DURING PAST
AND  AGE                  HELD WITH FUND       TIME SERVED*          FIVE YEARS
                                                          
OFFICERS:
ROBERT M. ETTINGER          President          Since               President and Director of
301 E. Colorado Boulevard                    October 2002          Flaherty & Crumrine
Suite 720                                                          Incorporated
Pasadena, CA 91101
Age: 48

R. ERIC CHADWICK            Chief Financial    Since               Director of Flaherty & Crumrine
301 E. Colorado Boulevard    Officer, Vice    October 2002         Incorporated since June 2006; Vice
Suite 720                    President and                         President of Flaherty & Crumrine
Pasadena, CA 91101         Treasurer                               Incorporated since August 2001
Age: 32

CHAD C. CONWELL             Chief Compliance   Since               Chief Compliance Officer of
301 E. Colorado Boulevard     Officer, Vice   July 2005            Flaherty & Crumrine Incorporated
Suite 720                    President and                         since September 2005, Vice President of
Pasadena, CA 91101              Secretary                          Flaherty & Crumrine Incorporated
Age: 34                                                            since July 2005; Attorney with Paul,
                                                                   Hastings, Janofsky & Walker LLP from
                                                                   September 1998 through June 2005

BRADFORD S. STONE           Vice President     Since               Director of Flaherty & Crumrine
392 Springfield Avenue      and Assistant     July 2003            Incorporated since June 2006; Vice
Mezzanine Suite              Treasurer                             President of Flaherty & Crumrine
Summit, NJ 07901                                                   Incorporated since May 2003;
Age: 47                                                            Director of U.S. Market Strategy at
                                                                   Barclays Capital from June 2001 to
                                                                   April 2003

LAURIE C. LODOLO              Assistant        Since
301 E. Colorado Boulevard     Compliance      July 2004            Assistant Compliance Officer of
Suite 720                  Officer, Assistant                      Flaherty & Crumrine Incorporated
Pasadena, CA 91101           Treasurer and                         since August 2004; Secretary of
Age: 43                    Assistant Secretary                     Flaherty & Crumrine Incorporated since
                                                                   February 2004; Account Administrator
                                                                   of Flaherty & Crumrine Incorporated
                                                                   since January 1987


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Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
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BOARD CONSIDERATION AND APPROVAL OF CONTINUANCE OF INVESTMENT ADVISORY
AGREEMENT

     During the six month period  ended May 31, 2007,  the Board of Directors of
the Fund approved the continuation of the investment advisory agreement with the
Adviser (the  "Agreement").  The  following  paragraphs  summarize  the material
information  and factors  considered  by the Board,  including  the  Independent
Directors, as well as their conclusions relative to such factors.

     In considering  whether to approve the Fund's Agreement,  the Board members
considered  and  discussed a  substantial  amount of  information  and  analysis
provided,  at the  Board's  request,  by the  Adviser.  The Board  members  also
considered  detailed  information  regarding  performance  and expenses of other
investment  companies thought to be generally  comparable to the Fund. The Board
members  discussed with  management this and other  information  relating to the
Agreements during the Special Meeting held on January 12, 2007 for that specific
purpose and requested  additional  information  about comparative  expenses.  In
reaching their  determinations  relating to  continuance  of the Agreement,  the
Board members  considered these  discussions and all other factors they believed
relevant,  including the factors  discussed below. In their  deliberations,  the
Board members did not identify any particular information that was all-important
or controlling,  and Board members may have attributed  different weights to the
various factors.  The Board members  evaluated this  information,  and all other
information  available to them, for the Fund, and their determinations were made
separately in respect of each other fund advised by the Adviser.  In particular,
as they had in past  years,  the Board  members  focused on the  following  with
respect to the Fund.

NATURE,  EXTENT AND QUALITY OF SERVICES

     The Board members  reviewed in detail the nature and extent of the services
provided by the Adviser and the quality of those services over the past year and
since inception.  The Board members noted that these services  included managing
the Fund's investment program, as well as providing  significant  administrative
services  beyond what the Agreement  required.  The Board members noted that the
Adviser also provided,  generally at its expense:  office  facilities for use by
the  Fund;   personnel   responsible   for   supervising   the   performance  of
administrative,  accounting  and related  services;  and  investment  compliance
monitoring.  The Board members also  considered  the Adviser's  sound  financial
condition  and the Adviser's  commitment  to its  business,  as evidenced by its
hiring  additional  personnel  as the  business  has  grown.  The Board  members
evaluated the Adviser's  services  based on their direct  experience  serving as
Directors  for  many  years,  focusing  on (i) the  Adviser's  knowledge  of the
preferred  securities market generally and the sophisticated  hedging strategies
the Fund employs and (ii) the Adviser's culture of compliance. The Board members
reviewed  the  personnel  responsible  for  providing  services  to the Fund and
observed that, based on their  experience and interaction with the Adviser:  (1)
the Adviser's personnel exhibited a high level of personal integrity,  diligence
and  attention  to  detail in  carrying  out  their  responsibilities  under the
Agreement;  (2) the  Adviser  was  responsive  to  requests of the Board and its
personnel were available  between Board meetings to answer  questions from Board
members;  and (3) the  Adviser  had  kept the  Board  apprised  of  developments
relating to the Fund. The Board members also  considered  the continued  efforts
undertaken by the Adviser to maintain an effective

                                       36



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compliance program.  The Board members  concluded that the  nature and extent of
the services provided were reasonable and  appropriate in relation to the Fund's
investment goals  and  strategies,  the corporate and regulatory environment  in
which the Fund operates,  and the  level of  services provided  by the  Adviser,
and that the quality of the Adviser's service continues to be high.

INVESTMENT PERFORMANCE

     The Board  members  considered  the  Fund's  performance  since  inception,
including its  performance in recent fiscal  periods,  to determine  whether the
Fund had met its investment  objective.  The Board members  determined  that the
Fund  had  done  so,  especially  in  light  of  existing  extraordinary  market
conditions,  which include rising  short-term  rates and a relatively flat yield
curve, conditions that reduce hedging benefits. In reaching this conclusion, the
Board members reviewed the Fund's  performance  compared to relevant indices and
funds thought to be generally  comparable to the Fund,  considered the costs and
benefits of the Fund's hedging  strategy in the relevant market  environment and
examined the  differences  between the Fund and certain funds in the  comparison
group,  including the  significant  positions in common  equities of a number of
preferred  stock  funds.  The Board  members  noted the Fund's  adherence to its
respective  investment  mandate.  The Board members also  considered that recent
relative  underperformance was attributable largely to the Fund's stated hedging
strategies,  which have been a central aspect of the Fund's  investment  program
since inception.

PROFITABILITY

     The Board members considered the Adviser's  methodology for determining its
profitability  with respect to the Fund,  and the Adviser's  profit margin on an
after-tax basis  attributable to managing the Fund. The Board members  concluded
that  the   profitability  to  the  Adviser  was  not  excessive  based  on  the
considerable  services it provides to the Fund, the Fund's relative  performance
over time, its success in meeting the Fund's investment objective and the Fund's
relatively  low  expense  ratio  compared  to  funds  with  similar   investment
objectives and  strategies.  The Board members also  considered that the Adviser
provided,  at a lower cost,  services to separate account clients and determined
that the difference was justified in light of the additional  services and costs
associated with managing registered investment companies,  such as the Fund. The
Board members accepted the Adviser's  statement that it did not realize material
indirect  benefits from its  relationship  with the Fund and did not obtain soft
dollar credits from securities trading.

ECONOMIES OF SCALE

     The Board members noted that the Fund, as a closed-end  investment company,
was not expected to increase  materially  in size;  thus,  the Adviser would not
benefit from economies of scale. The Board members  considered whether economies
of scale could be realized  because the Adviser  advises  other  similar  funds.
Based on their experience,  the Board members accepted the Adviser's explanation
that  significant  economies  of scale  would  not be  realized  because  of the
complexity  of  managing  preferred  securities  for  separate  funds  and other
portfolios.  Nonetheless,  the Board members noted that the Fund's  advisory fee
schedule declines as assets increase beyond a certain level (commonly known as a
"breakpoint"),  and that breakpoints  provide for a sharing with shareholders of
benefits derived as a

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result  of  economies  of  scale  arising  from  increased assets.  Accordingly,
the Board members determined  that  the  existing  advisory  fee  levels reflect
possible economies of scale.

     In light of their  discussions and  considerations  as described above, the
Board members made the following determinations as to the Fund:

     o the nature and extent and quality of the services provided by the Adviser
       are reasonable and appropriate  and the  quality of the services is high;

     o the Fund's overall performance was satisfactory, given market conditions;

     o the fee paid to the Adviser was reasonable in light  of  (i)  comparative
       performance and expense and advisory fee information,  (ii) the  cost  of
       the services provided and profits to be realized, and (iii) the  benefits
       derived or to be derived by the Adviser from the  relationship  with  the
       Fund; and

     o there were not at this time significant economies of scale to be realized
       by the Adviser in managing the Fund's  assets, and the fee was structured
       to provide for a sharing of the benefits of economies of scale.

     Based on these  conclusions,  the Board members determined that approval of
the Agreement was in the best interests of the Fund and its shareholders.

                                       38



DIRECTORS
  Donald F. Crumrine, CFA
    Chairman of the Board
  David Gale
  Morgan Gust
  Karen H. Hogan
  Robert F. Wulf, CFA

OFFICERS
  Donald F. Crumrine, CFA
    Chief Executive Officer
  Robert M. Ettinger, CFA
    President
  R. Eric Chadwick,  CFA
    Chief Financial Officer,
    Vice President and Treasurer
  Chad C. Conwell
    Chief  Compliance Officer,
    Vice  President and Secretary
  Bradford S. Stone
    Vice President and
    Assistant Treasurer
  Laurie C. Lodolo
    Assistant  Compliance Officer,
    Assistant  Treasurer and
    Assistant Secretary

INVESTMENT ADVISER
  Flaherty & Crumrine Incorporated
  e-mail: flaherty@pfdincome.com

QUESTIONS CONCERNING YOUR SHARES OF  FLAHERTY &
  CRUMRINE  PREFERRED  INCOME  OPPORTUNITY  FUND?
  o If your shares are held in a brokerage
    Account, contact your broker.
  o If you have physical possession of your shares
    in certificate form, contact the Fund's Transfer
    Agent & Shareholder Servicing Agent --
            PFPC Inc.
            P.O. Box 43027
            Providence, RI 02940-3027
            1-800-331-1710

THIS  REPORT IS SENT TO  SHAREHOLDERS  OF FLAHERTY & CRUMRINE  PREFERRED  INCOME
OPPORTUNITY  FUND  INCORPORATED FOR THEIR  INFORMATION.  IT IS NOT A PROSPECTUS,
CIRCULAR OR REPRESENTATION INTENDED FOR USE IN THE PURCHASE OR SALE OF SHARES OF
THE FUND OR OF ANY SECURITIES MENTIONED IN THIS REPORT.

[GRAHIC OMITTED - LIGHTHOUSE ART]

FLAHERTY & CRUMRINE
PREFERRED INCOME
OPPORTUNITY FUND


SEMI-ANNUAL
REPORT


MAY 31, 2007

www.preferredincome.com



ITEM 2. CODE OF ETHICS.

Not applicable.



ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT.

Not applicable.



ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES.

Not applicable.



ITEM 5. AUDIT COMMITTEE OF LISTED REGISTRANTS.

Not applicable.



ITEM 6. SCHEDULE OF INVESTMENTS.

Schedule of Investments in securities of unaffiliated issuers as of the close of
the  reporting  period is included as part of the report to  shareholders  filed
under Item 1 of this form.



ITEM 7. DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR CLOSED-END
        MANAGEMENT INVESTMENT COMPANIES.

Not applicable.



ITEM 8. PORTFOLIO MANAGERS OF CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

There has been no change, as of the date of this filing, in any of the portfolio
managers  identified  in  response  to  paragraph  (a)(1)  of  this  Item in the
registrant's most recently filed annual report on Form N-CSR.



ITEM 9.  PURCHASES OF EQUITY  SECURITIES  BY  CLOSED-END  MANAGEMENT  INVESTMENT
         COMPANY AND AFFILIATED PURCHASERS.

Not applicable.



ITEM 10. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

There have been no material  changes to the procedures by which the shareholders
may  recommend  nominees to the  registrant's  board of  directors,  where those
changes were  implemented  after the  registrant  last  provided  disclosure  in
response to the  requirements  of Item  407(c)(2)(iv)  of Regulation S-K (17 CFR
229.407) (as required by Item  22(b)(15) of Schedule 14A (17 CFR  240.14a-101)),
or this Item.


ITEM 11. CONTROLS AND PROCEDURES.

    (a)  The registrant's  principal executive and principal financial officers,
         or  persons  performing  similar  functions,  have  concluded  that the
         registrant's  disclosure  controls and  procedures  (as defined in Rule
         30a-3(c)  under the  Investment  Company Act of 1940,  as amended  (the
         "1940 Act") (17 CFR 270.30a-3(c)))  are effective,  as of a date within
         90 days of the filing date of the report that  includes the  disclosure
         required by this paragraph, based on their evaluation of these controls
         and  procedures  required by Rule  30a-3(b)  under the 1940 Act (17 CFR
         270.30a-3(b))  and Rules  13a-15(b) or 15d-15(b)  under the  Securities
         Exchange   Act  of  1934,   as  amended   (17  CFR   240.13a-15(b)   or
         240.15d-15(b)).


    (b)  There  were  no  changes  in the  registrant's  internal  control  over
         financial reporting (as defined in Rule 30a-3(d) under the 1940 Act (17
         CFR 270.30a-3(d))  that occurred during the registrant's  second fiscal
         quarter  of the  period  covered  by this  report  that has  materially
         affected,   or  is  reasonably   likely  to  materially   affect,   the
         registrant's internal control over financial reporting.


ITEM 12. EXHIBITS.

     (a)(1)   Not applicable.

     (a)(2)   Certifications  pursuant to Rule  30a-2(a)  under the 1940 Act and
              Section 302 of the Sarbanes-Oxley Act of 2002 are attached hereto.

     (a)(3)   Not applicable.

     (b)      Certifications  pursuant to Rule  30a-2(b)  under the 1940 Act and
              Section 906 of the Sarbanes-Oxley Act of 2002 are attached hereto.



                                   SIGNATURES

Pursuant to the  requirements  of the  Securities  Exchange  Act of 1934 and the
Investment Company Act of 1940, the registrant has duly caused this report to be
signed on its behalf by the undersigned, thereunto duly authorized.

(registrant) FLAHERTY & CRUMRINE PREFERRED INCOME OPPORTUNITY FUND INCORPORATED

By (Signature and Title)* /S/ DONALD F. CRUMRINE
                         -------------------------------------------------------
                         Donald F. Crumrine, Director, Chairman of the Board and
                         Chief Executive Officer
                         (principal executive officer)

Date              JULY 23, 2007
    ----------------------------------------------------------------------------


Pursuant to the  requirements  of the  Securities  Exchange  Act of 1934 and the
Investment  Company  Act of  1940,  this  report  has been  signed  below by the
following  persons on behalf of the  registrant and in the capacities and on the
dates indicated.


By (Signature and Title)* /S/ DONALD F. CRUMRINE
                         -------------------------------------------------------
                         Donald F. Crumrine, Director, Chairman of the Board and
                         Chief Executive Officer
                         (principal executive officer)

Date              JULY 23, 2007
    ----------------------------------------------------------------------------


By (Signature and Title)*  /S/ R. ERIC CHADWICK
                         -------------------------------------------------------
                           R. Eric Chadwick,  Chief Financial Officer, Treasurer
                           and  Vice  President
                           (principal financial officer)

Date              JULY 23, 2007
    ----------------------------------------------------------------------------



* Print the name and title of each signing officer under his or her signature.