James Vernon, a co-founder and chief operating officer, of Brevan Howard Asset Management is to leave the firm in September to pursue other interests. He is the most senior executive left in London after co-CEO Nagi Kawkabani earlier this year joined Alan Howard and a team of the firm’s top traders already based in Geneva.

“(Vernon) has played a valuable part in building the business’ global platform and infrastructure,” the hedge fund group said in a statement to investors. “We thank him for his contribution and wish him well in his future endeavours.”

Vernon is to continue to act as a non-executive board member of Brevan Howard’s non-UCITS funds. These include the flagship Brevan Howard Master Fund which with assets of over $24 billion accounts for 80% of the firm’s assets under management.

Vernon, who represented the ‘V’ in Brevan Howard. The first word of the firm’s name is made up of the initials of founding partners Jean-Philippe Blochet, Christopher Rokos, Vernon and Trifon Natsis.

Vernon is the second founding partner to leave the firm after Blochet joined Moore Capital last year. Blochet quit the Moore’s New York operation in May to concentrate on philanthropy.

Brevan Howard is expected to appoint a new COO in the coming weeks. It remains unclear where the position will be based but most of Brevan’s non-portfolio management staff continue to be based at its facilities in Baker Street, London.