Financial institutions that issue ETFs are called ETF sponsors. ETF sponsors could be banks or institutional investment firms. The largest ETF sponsor is BlackRock’s iShares. iShares was created by Barclays’ Global Investors, which in turn was acquired by BlackRock. As of early 2018, iShares had more than $1.75 trillion of assets under management, which made up more than one-fourth of BlackRock’s total AUM. The other major players are Vanguard, State Street Global Advisors, Deutsche Bank, and Investgo. ETF sponsors, like mutual funds, earn fees as a percentage of assets under management. That is, if an ETF sponsor is managing one billion dollars in investments, while charging 0.1 percent in fees annually, then the ETF sponsor is earning 0.1 percent times one billion dollars or one million dollars per year. ETF fees are much smaller percentages compared to the fees charged by mutual funds and hedge funds. But the large volume of assets invested make ETFs very profitable for ETF sponsors. The ETF sponsor designs and maintains the ETF portfolio, so you can think of them as the fund manager. So far, ETFs sound pretty similar to mutual funds.