All 13 categories gained in absolute terms, according to the report. The Size category accounted for 43% of the $21.5 billion gained overall.
By style, Large Cap had the largest gain in assets, climbing $6.7 billion, followed by Small Cap, up $1.7 billion. Gains were spread evenly among nine of the ten Sectors for a cumulative gain of $3.4 billion.
The top three managers in the U.S. ETF marketplace in February were BlackRock, State Street Global Advisors (State Street), and Vanguard. Collectively, they accounted for approximately 83.8% of the U.S.-listed ETF market.
The top three U.S. ETFs in terms of dollar volume traded for the month were the SPDR S&P 500 [SPY], PowerShares QQQ [QQQQ], and iShares Russell 2000 [IWM].
More information is at http://www.spdrs.com.