Comparing units outstanding versus one week ago at the coverage universe of ETFs at ETF Channel, the biggest inflow was seen in the PowerShares S&P 500 Low Volatility Portfolio (SPLV), which added 23,800,000 units, or a 15.9% increase week over week. Among the largest underlying components of SPLV, in morning trading today Xcel Energy (XEL) is off about 0.7%, and Duke Energy Corporation Holding Company (DUK) is lower by about 0.4%.