The bullies of Wall Street are taking a beating from the market.

Activist hedge funds lost just over 6.1% in January, according to Hedge Fund Research, which released its monthly numbers on Friday. That was the worst monthly performance of any hedge fund strategy that HFR tracks, outside of individual sector funds. It was also the worst monthly performance logged by activist hedge funds in more than three-and-a-half years, and the fourth worst monthly performance these funds have had since HFR began tracking their returns in 2008.

As a group, hedge funds overall lost nearly 2.9% in January, a disappointing month for the funds, which generally charge high fees on the assumption that they can make money when very few other investors can. Hedge funds in general lost less than the rest of the market, which was down 5%, as measured by the S&P 500. Activist hedge funds can’t make that claim, though.

Some of the best known activist hedge funds did a good deal worse than the rest of the pack. The publicly traded portion of Bill Ackman’s Pershing Square Capital fell 11% in January.

Trian Partners, the hedge fund run by former corporate raider Nelson Peltz, which took on DuPont dd last year, has also been one of the worst performing funds this year. DuPont’s shares have fallen more than 11% this year, even after agreeing to be bought by Dow Chemical, a deal that was supported by Peltz. In all, Peltz’s fund was down nearly 9.5% in the first three weeks of January, according to a hedge fund ranking by HSBC.

Marcato, another activist fund—which is run by Robert McGuire, who used to work at Pershing Capital—also had big losses in January. Its international fund was down 10.5% in the first three weeks of 2016, according to HSBC.

Carl Icahn doesn’t disclose his returns. But shares of his publicly held Icahn Enterprises iep are down 16% this year.

Hedge funds are supposed to function as a buffer to the ups and downs of the market; hence the word “hedge” in their name. If activist hedge funds can’t do that, they risk losing their influence with investors and, ultimately, their ability to make corporate boards do their bidding.