U.S. equity funds, including mutual and exchange-traded funds (ETFs), posted the largest outflows ever recorded in the last weeks of March, the Institute of International Finance said Thursday.

The $40 billion of outflows in the second half of last month marked the highest dollar amount ever leaving U.S. equity funds, a result of investor uncertainty over the rising U.S. fiscal deficit, growing trade war fears, the Federal Reserve raising U.S. overnight interest rates and a number of other fears, IIF reported.

The IIF’s senior director, Sonja Gibbs, told Yahoo Finance the biggest thing on investors’ minds seems to be increasing tensions.

“No one really knows how all of this is going to play out and over what time frame,” Gibbs said. “Given that, the fact that it’s rattled the markets this much suggests that the focus is a little more on underlying worries.”

Investors pulled more money out of U.S. equity funds than ever before, a recent survey from a bank lobbying organization showed.

Gibbs noted that the growth of ETFs as well as investor capital in U.S. mutual funds exaggerated March’s outflows on a historical basis. Still, she said, “it has been a long time since there’s been a drop off like this.”

As a percentage of overall assets invested, the outflows IIF tracked in the second half of March were the largest since 2014, but they fall short of the bloodletting during the 2007-2009 financial crisis. Outflows reached more than 1.3% of total assets under management during the financial crisis, versus about 0.5% during this most recent market selloff, the data show.

Retail investors are fleeing

The outflows are also a reflection of the growing number of so-called retail investors or individuals who are investing for themselves or a few friends rather than institutional investors who are investing hundreds of millions to trillions of dollars…