Pershing Square Holdings had a May loss of 0.7 percent, following a gain of 10.2 percent in April that had helped shrink the loss for the first four months to 18 percent, an investor in the fund said. In the first quarter, Pershing Square Holdings lost 25.6 percent, one of the industry’s worst returns.

Other private Pershing Square portfolios, which use less leverage than Pershing Square Holdings, are down roughly 15 percent for the year to date, a person familiar with the funds said.

Ongoing losses have prompted the firm, whose assets under management are down by about 40 percent from a year ago to $12.3 billion, to tell investors that it expects redemptions for the second quarter to be higher than in recent quarters, two people familiar with the matter said.

This year’s losses follow a 20.5 percent drop in 2015, which followed a winning 2014 whenPershing Square ranked as one of the hedge fund industry’s best performers with a roughly 40 percent gain.

Ackman’s chief troubles this year are the same as last: bets that shares of drug company Valeant will climb and shares of nutrition company Herbalife’s will fall. Ackman joined Valeant’s board this year and helped pick a new chief executive.

Other funds have also struggled this year. Barry Rosenstein, often among the first to report monthly numbers, on Tuesday told investors that his Jana Partners fund is off 4.7 percent this year after gaining 2.4 percent last month. David Einhorn’s Greenlight Capital fell 1.9 percent in May but is up 1.1 percent this year, according to data provided to Reuters by sources.

The depth and prolonged period of Ackman’s declines, however, stand out in the industry and have made some investors uneasy, several said. Ackman has been spending time visiting clients in the last months to explain his vision for the fund in greater and more personal detail.

With investors generally souring on hedge funds – $14 billion in assets were pulled in the first quarter alone, according to data from Preqin – Pershing Square is one fund that may see more substantial redemptions in the months ahead, investors said.

Pershing Square allows most clients to pull only one-eighth of their money per quarter, which means it would take two full years to exit Pershing Square completely.

Historically, quarterly redemptions have averaged 2.2 percent of assets. At the start of this year, that number was lower, with investors asking for only about 2 percent back, two people said.

But that number is expected to be higher in the second quarter.

To get money out by the end of June, investors had to notify Pershing Square by April 29, though they may still change their minds and withdraw redemption notices, making it unclear how much money will be pulled in the second quarter.

A year ago Pershing Square managed $19.7 billion. The firm’s structure includes permanent capital at one of its portfolios plus employee capital and a public bond issue which assure that assets cannot drop to zero.

Correction: This version of the story adds details on the fund and redemptions.