Felix Rohatyn has become the third rainmaker in a month to sell his advisory boutique during a boom year for mergers and acquisitions.

The decision by Rohatyn, a former US ambassador to France, to fold his boutique into Lehman Brothers comes a month after two JP Morgan bankers shared more than $50m (€39m) by selling their boutique to Evercore Partners, the US advisory firm that floated in New York earlier this month.