(Adds comment by Lazard CEO, source close to Pigasse)
By Gwénaëlle Barzic
PARIS, Oct 20 (Reuters) - French banker Matthieu Pigasse is to leave Lazard after 17 years to pursue a new entrepreneurial project, an exit that will see the firm lose one of its biggest rainmakers.
For Lazard, Pigasse has led the world's largest sovereign debt restructurings in Greece, Argentina and Ukraine, as well as multi-billion mergers such as those between Unibail-Rodamco and Westfield, Sanofi and Boehringer Ingelheim, Safran and Zodiac.
"I am excited to begin my next chapter beyond investment banking in a new entrepreneurial project," Lazard cited Pigasse as saying.
Pigasse has been reflecting on his future for about eight months, a source close to the banker said, adding that he took the decision only in the last few days. Lazard did not want to let him go, the source said, but Pigasse needed a new challenge.
His departure follows rumours about the future of the flamboyant 51-year-old Pigasse, a punk rock aficionado who has deep relationships with members of the French establishment.
Reuters reported earlier this month that he had talked to several U.S. boutique investment banks.
In May this year, Lazard announced a reshuffle of its senior leadership, with Pigasse named global head of banking and deputy CEO of financial advisory, while also retaining his job as chairman and chief executive of Lazard France.
Lazard CEO Kenneth Jacobs said at the time that Pigasse was "central to our success in France and elsewhere" and that his new focus would be to help the firm's new CEO of financial advisory, Peter Orszag, win more business globally.
"It was not my decision, it was Matthieu's decision (to resign)," Jacobs, who is in Paris, told Reuters on Sunday in a statement sent via a Lazard spokesperson.
Pigasse is well-known in Paris business and media circles due to his shareholding in newspaper Le Monde and business interests in Radio Nova and Les Inrockuptibles cultural magazine.
He joined Lazard as a managing director in 2002, becoming its youngest ever partner.
The bank said it would announce a new leadership team in France shortly. (Reporting by Gwenaelle Barzic; Writing by Maya Nikolaeva; Editing by Angus MacSwan and Daniel Wallis)