Comparing units outstanding versus one week ago at the coverage universe of ETFs at ETF Channel, the biggest inflow was seen in the iShares Russell 2000 ETF (IWM), which added 10,000,000 units, or a 4.3% increase week over week. Among the largest underlying components of IWM, in morning trading today Acuity Brands (AYI) is down about 1.1%, and athenahealth (ATHN) is lower by about 1.3%.