The head of Barclays' global financial institutions group, Jeff Weiss, is retiring after nearly three decades at the British bank and Lehman Brothers, according to an internal memo seen by Reuters on Thursday.

Weiss, who also served on the executive committee of investment banking, is leaving to pursue entrepreneurial opportunities, said the memo, which was signed by Skip McGee, the head of Global Investment Banking at Barclays.

Weiss served in his role at Barclays since 2008, and held the same title at Lehman Brothers from 2007 to 2008. He started his career in 1983 as a corporate bond trader at Lehman Brothers.

A Barclays spokesman confirmed the contents of the memo.

Recent transactions in which Barclays' financial services group has played a role include serving as special adviser to the board of U.S. insurer MetLife Inc in its acquisition of American International Group Inc unit ALICO for about 9.7 billion pounds and Prudential Financial Inc's
acquisition of certain AIG subsidiaries for $4.8 billion.

The group has also advised Capital One Financial Corp in several transactions, including on its $9 billion purchase of ING Direct and the related $2 billion forward sale of equity.

(Reporting By Paritosh Bansal; editing by Gunna Dickson)