By Echo Wang and Isla Binnie

NEW YORK, Nov 21 (Reuters) - Just a few years after a bruising battle among Apollo's APO.N co-founders over succession, the alternative asset manager giant could face new upheaval if its chairman and chief executive both leave to work for U.S. President-elect Donald Trump.

Wall Street was raking over the possibilities after Trump picked Jay Clayton, Apollo's board chair, to serve as Manhattan's top federal prosecutor, while sources said Marc Rowan, the firm's CEO, was being considered for the Treasury Secretary role.

TD Cowen analysts said they were fielding calls on the implications and who might replace Rowan, as investors balanced the chances that senior government appointments could boost the industry with the challenge of changing the guard at the $722 billion manager.

"Such an outcome would be a positive for the industry, as it likely tempers regulatory risk(s) while possibly accelerating the sector's entry into the retirement market, even beyond his official purview," the analysts said in a note to clients, referring to speculation about Rowan.

Co-presidents Jim Zelter and Scott Kleinman, as well as a few other key executives could be likely successors as CEO, the TD Cowen analysts said.

Apollo declined to comment.

In a sign of Rowan's importance to Apollo, however, the alternative asset manager's stock slipped on Tuesday amid reports that he had emerged as a top contender for the Treasury job. It was up as much as 1.8% on Thursday afternoon.

Rowan, who co-founded Apollo along with Leon Black and Josh Harris, stepped into the CEO role in 2021 after a messy succession process, set in motion by Black's association with convicted sex offender Jeffrey Epstein.

An independent review commissioned by Apollo had found Black paid Epstein for some services but was not involved in any way with his criminal activities.

The events also led to a dispute between the co-founders, which resulted in Harris departing the firm as well.

Clayton, the former U.S. Securities and Exchange Commission chief, was appointed as its lead independent director to improve corporate governance in the wake of the events.

Under Rowan, Apollo has been charting a new growth strategy, going far beyond its private equity origins.

Apollo bought retirement services firm Athene Holding Ltd in an $11 billion all-stock transaction, a deal that came weeks after Rowan came out of a sabbatical to become the CEO.

Bringing in-house an annuities provider has helped turn Apollo into one of the world's largest corporate credit investors.

In its regulatory filings, Apollo said it depends on some key employees, although it does not name them.

"The loss of the services of any of our key personnel or damage to their personal reputation could have a material adverse effect on our business," the firm says in its annual report.

(Reporting by Echo Wang and Isla Binnie in New YorkEditing by Alistair Bell)

((E.Wang@thomsonreuters.com; +13322191785; Reuters Messaging: @deer_echo_))