About two-thirds of the capital that investors could withdraw from Pershing Square Capital Management’s private funds was redeemed at the end of last year, according to a person with knowledge of the matter.

Blackstone Group LP has been pulling its money, while JPMorgan Chase & Co. has removed Bill Ackman’s Pershing Square from its list of recommended funds for clients, the person said. The Wall Street Journal reported the news of the redemptions earlier, citing people it didn’t identify.

A representative for Pershing Square declined to comment. Spokesmen for Blackstone and JPMorgan either didn’t immediately comment or didn’t respond to a request.

In a letter to investors published last month, Ackman pledged to end three years of underperformance, calling recent returns “particularly unsatisfactory.” Pershing Square has been restructuring into a smaller, investment-centric organization whose future asset growth will be driven by results, the billionaire investor wrote.

Pershing Square Holdings Ltd., the U.K.-listed firm that controls a separate pool of money from the private fund, had a net loss of 4 percent last year, compared to a 22 percent gain on the broader S&P 500 benchmark index during the same period. The biggest hits to the portfolio came from its investments in Herbalife Ltd. and Mondelez International Inc.

The private fund’s rules dictate that investors are eligible to remove no more than one-eighth of their money every quarter, meaning that it would take two years to fully redeem their investments, the person said.

This article was provided by Bloomberg News.