Yoel Zaoui of goldman sachs group is accustomed to spending his time talking to chief executives about deals. But Goldman’s head of investment banking for Europe, the Middle East and Africa spent the weekend of April 17, 2010, talking to many of them about his firm, which had just been sued by the U.S. Securities and Exchange Commission over a 2007 collateralized debt obligation transaction known as Abacus.

Zaoui took the potential fallout very seriously, especially as critics predicted it could hurt the bank’s most valuable client business: its M&A franchise. Goldman (which settled the case last June without admitting wrongdoing) embarked on what Zaoui calls “a big exercise of introspection whilst redoubling our efforts with our clients.”

A lot was at stake for the 49-year-old Zaoui, who was one of only a handful of executives responsible for building Goldman’s European investment banking business from scratch, beginning in 1989. “At that time, investment banking was the new thing, and I was asked to go to Europe and start Goldman’s business there,” he recalls.

Zaoui didn’t hesitate. “I was drawn to the idea of striking up a personal rapport with executives and becoming a trusted adviser to a company,” he explains. Plus, he enjoys the cut-and-thrust of deal making: “For me, to develop a really good relationship, you have to be able to disagree with a client, and for it to be a comfortable conversation.” Then there is what he calls his “paranoia” — viewing a deal from every possible angle to identify any obstacles to success. These qualities — combined with fluency in English, French, Italian and Spanish — brought Zaoui and Goldman unparalleled success in Europe, where the firm progressed from providing defense advice alongside such venerable City of London institutions as S.G. Warburg & Co. to becoming the Continent’s top M&A adviser.

Along the way, Zaoui played a key role in some of the region’s most high-profile deals, including helping three French companies fend off hostile takeovers by rivals: oil concern Elf Aquitaine against Total Fina in 1999, aluminum maker Pechiney against Alcan in 2003 and pharmaceuticals manufacturer Aventis against Sanofi-Synthélabo in 2004; all three cases resulted in friendly mergers. More recently, in August, Zaoui was a lead adviser for GDF Suez’s reverse acquisition of the U.K.’s International Power.