Goldman Sachs Group Inc announced on Friday a management shuffle atop its investment management division, according to internal memos.

Marc Spilker, 45 years old and a 20-year Goldman veteran, is leaving, and will be replaced by Edward Forst as co-head of the firm's investment management division, the memos said.

Spilker, co-head of the investment management division and a member of the management committee, has retired.

Goldman Chief Executive Lloyd Blankfein said in a memo that Spilker was responsible for mentoring colleagues who have become important leaders at Goldman.

Forst, Goldman's senior strategy officer, will lead the investment management division with Tim O'Neill.

Forst rejoined Goldman last year after serving for one year as an executive with Harvard University. He originally joined the firm in 1994 and rose to head the investment management division.

A Goldman spokeswoman confirmed contents of the memos.

(Reporting by Steve Eder; Editing by Gary Hill)