The U.S. exchange-traded product industry topped the $4 trillion mark by the end of July. To put that growth in perspective, it took U.S.-listed exchange-traded funds and products (the majority are ETFs) 18 years to reach $1 trillion in assets under management, 3.2 years to get to $2 trillion, 2.5 years to get to $3 trillion, and 2 years to hit $4 trillion, according to Deborah Fuhr, managing partner and founder of ETFGI, an ETF/ETP industry research and consulting firm.

According to ETFGI’s most recent report, assets in U.S.-listed ETFs/ETPs rose 1.6% in July, to end the month at $4.02 trillion. All told, ETFs/ETPs in the U.S. saw  $33.9 billion in net inflows in July. The top 20 asset gatherers gobbled up $26.2 billion of those inflows. The top three in inflows were the SPDR S&P 500 ETF Trust (SPY), iShares Core S&P 500 ETF (IVV) and Vanguard S&P 500 ETF (VOO).

Through July, the U.S. had 2,280 ETFs/ETPs from 151 providers listed on 3 exchanges.

While the U.S. ETF industry’s growth has been impressive during its roughly quarter-century existence, its total asset base is still less than one-quarter that of the U.S. mutual fund industry.