NEW YORK (TheStreet) -- CEO of Pershing Square (PSHZF) Bill Ackman is leaving Canadian Pacific, an investment Ackman has been a part of for five years and was the biggest jackpot of his career, CNBC's Scott Wapner reported on "Fast Money Halftime Report"Thursday. 

Pershing Square made $2.6 billion on Canadian Pacific, he said.

"It's a great example of how shareholder activism can create value for all stakeholders," Ackman told CNBC.

Pershing Square first got into Canadian Pacific in September 2011, built the stake over about a month with a price ranging from about $63 to $55, CNBC's Kate Kelly reported.

The company sold 6 million shares in late 2013 for about $142, it had two more sales in the next few years at a higher price range, and a final sale of 9.8 million shares yesterday, she said.

Pershing made most of its profit, about $2 billion on the stock's performance and from a currency hedge, she noted.

Pershing will use this sale to make more investments in the main fund, she added.

"The timing really couldn't be better," she said.

The fund is down 19% through July mostly due to Valeant Pharmaceutical's (VRX) negative performance which is down 78% year to date and issues with Herbalife (HLF) which recently settled charges from the FTC for $200 million, she explained.

The first half of the year the redemption rate was not terribly high relative to other years, Ackman said in a call from CNBC.

This sale is being called one of the greatest corporate turnarounds in corporate history, Wapner said.

Shares of PSHZF are trading lower today.