NEW YORK, Feb 13 (Reuters) -

Sculptor Capital, the hedge fund at the heart of a recent bitter takeover battle, is shaking up its top ranks as a handful of senior executives, including a prominent money manager, are leaving the firm.

Jimmy Levin, Sculptor's chief investment officer and executive managing partner, announced the departures and promotions in a memo to the firm that was seen by Reuters.

He said Chief Financial Officer Dava Ritchea is leaving for a "new opportunity," while chief legal officer David Levine will be "moving on." Louisa Church, head of the client partner group, EMEA, is also leaving, the memo said.

Also leaving is Ghassan Ayoub, who joined Sculptor more than two decades ago and was most recently an executive managing director and global head of convertible and derivative arbitrage at the firm, as well as a member of the portfolio committee. "Ghassan accomplished a tremendous amount over a long period of time here and we wish him well," Levin wrote in the memo.

Ayoub is moving to rival hedge fund Millennium, which manages $62 billion, two sources familiar with the matter said. Bloomberg first reported Ayoub's departure.

A spokesman for Millennium declined to comment.

The reordering of the top ranks comes only months after a fevered fight for the future of Sculptor, which was then the largest U.S. publicly traded hedge fund with some $33 billion in assets.

After the firm agreed to sell itself to real estate investment firm Rithm Capital, a group of well known investors including Saba Capital's Boaz Weinstein, Pershing Square Capital Management's Bill Ackman and Avenue Capital Group's Marc Lasry

tried to buy Sculptor for a higher price.

Drama centered around Levin's future with Rithm promising to keep him in place, arguing that investors preferred continuity. The Weinstein group would not have kept Levin in the role. Rithm completed the purchase of Sculptor late last year.

Levin wrote that Stephane Mantelin was promoted to global head of convertible and derivative arbitrage and joined the Portfolio Committee and Risk Committee.

Ellen Conti will be chief financial officer while Julie Siegel will be chief legal officer.

(Reporting by Svea Herbst-Bayliss; Editing by Franklin Paul and Leslie Adler)