George Walker, head of Goldman Sachs Asset Management's $70bn (€55bn) alternative investments division and cousin of US president George W Bush, has quit to become Lehman Brothers' global head of investment management.

Lehman Brothers said Walker would be made a managing director and a member of the bank's executive committee. His role at the helm of Lehman Brothers' asset management division, which has $188bn under management, will encompass traditional asset management, private investment and private equity.