Nobody owns more U.S. stocks than mutual funds. But with their position slipping, the question is how much longer can they control the market?

Mutual fund ownership of equities is at its lowest level in nearly 13 years, according to a research note from Goldman Sachs Group Inc. Meanwhile, exchange-traded funds are becoming an even bigger force in the stock market, the team led by Chief U.S. Equity Strategist David Kostin pointed out.

“We expect mutual funds will remain net sellers of equities given investor outflows and low liquidity,” the researchers wrote, noting that the level of stock ownership by mutual funds has been slipping since 2016 after leveling off during the economic recovery.

Mutual funds sold a total of $117 billion in stocks in 2016, while corporations make $584 billion in net purchases through buybacks and ETFs made $188 billion. ETFs are a relatively new vehicle in the market, having surpassed $3 trillion in assets in just 2015. Mutual funds, which have been around since before the Great Depression, have roughly $16 trillion in assets.

Here’s a look at how equity demand played out in 2016 across various types of investors.

Goldman anticipates that a similar pattern will play out for the rest of the year.

“Corporations and ETFs will continue to drive equity demand while mutual funds, households, and pension funds will remain net sellers of equities,” the researchers wrote.