Ondra Partners, the boutique founded by ex-Lehman Brothers executives Benoit D’Angelin and Michael Tory in 2008, is fast establishing a name for itself as the A-team of investment banking.

The 40-man advisory-only firm popped up again this week as adviser to French utility GDF Suez on its $21.5bn asset merger with UK peer International Power - the largest cross-border deal of the year, according to Dealogic. Goldman Sachs, Rothschild, Blackstone and BNP Paribas are also listed as advisers to the French company.