Comparing units outstanding versus one week ago at the coverage universe of ETFs at ETF Channel, the biggest inflow was seen in the SPDR S&P 500 ETF Trust (SPY), which added 23,202,116 units, or a 2.3% increase week over week. Among the largest underlying components of SPY, in morning trading today Apple (AAPL) is down about 0.8%, and Microsoft Corporation (MSFT) is lower by about 0.2%.