Massive doesn't begin to describe the move into the ProShares Ultra 7-10 Year Treasury ETF (UST) last Wednesday as the $12M AUM fund went to $833M overnight. It was accompanied by a 53% increase in the $3.75B iShares 3-7 Year Treasury Bond ETF (IEI), suggesting someone (or ones) making a large bet targeting the middle of the Treasury curve. The moves came following FOMC minutes at which it indicated a readiness to increase QE as needed.