The capital management firm sold its 9.8 million shares in CP with JPMorgan Chase, Credit Suisse and Bank of America Merrill Lynch acting as underwriters for the offering, according to a CP press release.
Pershing Chief Executive Officer William Ackman will remain on CP's board until the Class I's next annual meeting, according to a Pershing Square press release.
"Canadian Pacific has completed an incredible transformation since our initial investment in 2011," said Ackman. "Hunter Harrison and Keith Creel have restored to greatness one of North America's top railroads and have set the company on the path to continued success."
Pershing Square intends to use the sale proceeds to fund new investments, the firm said.
In 2011, Ackman led Pershing Square's acquisition of a 14.2 percent stake in CP and pushed for the removal of board members and management, including the Class I's then-CEO Fred Green. After Green resigned, Ackman touted E. Hunter Harrison — the former president and CEO of CP competitor CN — as CP's candidate to replace Green.
Harrison joined CP as CEO in June 2012. Harrison brought on Keith Creel, his former right-hand man at CN, to serve as CP's president and chief operating officer.
In July, CP announced that Creel will succeed Harrison as CP's CEO on July 1, 2017.