Looking at units outstanding versus one week prior within the universe of ETFs covered at ETF Channel, the biggest outflow was seen in the SPDR S&P Oil & Gas Exploration & Production ETF (XOP), where 3,900,000 units were destroyed, or a 26.0% decrease week over week. Among the largest underlying components of XOP, in morning trading today Goodrich Petroleum (GDP) is off about 2.6%, and Comstock Resources (CRK) is lower by about 2.2%.