May 30 (Reuters) - Billionaire hedge fund manager Bill

Ackman is considering endorsing Donald Trump as the former U.S.

president seeks to return to the White House, a source familiar

with the matter said.

Ackman plans to announce which candidate he will endorse on

the social media network X, the source said, confirming an

earlier report by the Financial Times. He has 1.2 million

followers on X.

It would mark a change from 2021. Following the U.S. Capitol

attack on Jan. 6, Ackman wrote on the social media platform that

Trump should "resign and apologize to all Americans."

Ackman's firm Pershing Square Capital Management manages $18

billion in assets, most of it in a fund that is publicly listed

in Europe.

Last week Blackstone CEO Stephen Schwarzman said he

would support Trump in the U.S. election. Schwarzman said he was

motivated by "the dramatic rise of antisemitism" in the country

and concerns about the current state of the economy, immigration

and foreign policies.

Other money managers have not yet publicly announced their

endorsements. Citadel's founder Ken Griffin said earlier this

month that he had not donated money to Trump's election campaign

and that he would wait to see who the former U.S. leader picks

as his running mate.