William 'Bill' Ackman, CEO and Portfolio Manager of Pershing Square Capital Management, speaks during the Sohn Investment Conference in New York City, U.S., May 8, 2017. REUTERS/Brendan McDermid

NEW YORK (Reuters) - Activist investor William Ackman told his hedge fund clients on Wednesday that he liquidated positions in Air Products and Chemicals Inc and Nomad Foods Ltd, investments that earned them a lot of money.

In a letter sent late on Wednesday and seen by Reuters, Ackman said investors in funds run by his Pershing Square Capital Management made a 35 percent gain on Nomad Foods in just over two years.

At Air Products and Chemicals Inc. investors earned a 104.7 percent return during Pershing Square’s 4-1/2 year long investment. Before he arrived, Air Products was an industry laggard, Ackman wrote.

With new management and a board that worked collaboratively, Air Products is “now the most profitable company in the industrial gas industry,” he said.

Ackman noted problems as well including a tumble in Chipotle Mexican Grill’s stock after a food safety issue in July. “We are working with the new Chipotle board and management to assist the company in turning around its operations,” Ackman wrote.

In the third quarter, Ackman’s Pershing Square Holdings Ltd fund lost 3.7 percent, the letter said.

In his letter, Ackman, who often seeks to replace top management in target companies, mentioned Chipotle’s new Chief Restaurant Officer Scott Boatwright and Chief Digital and Information Officer Curt Garner but no one else.

He also sought to put a positive light on last week’s lost proxy contest at Automatic Data Processing where he wanted three board seats.

He said that management’s commitments to make improvements should pay off for his investors. But he added: “If management fails to deliver, we will be focused on next year’s annual meeting.”