The chief executive of Topaz Energy and Marine, the Renaissance Services unit which pulled a planned London float earlier this year, is leaving the company, two sources said on Thursday.

Fazel Fazelbhoy's resignation comes three months after Topaz pulled its $500 million London listing amid valuation concerns and growing regional unrest.

Fazelbhoy, who spent 11 years with Topaz, was appointed chief executive in January 2008. He had also headed Renaissance's ship repair business, NICO International.

One source said the reason for the departure could be Topaz's failed IPO plan earlier this year. The sources did not want to be identified because the information has not been made public yet.

Topaz -- one of the biggest oil services companies in the Middle East -- had launched its $500 million IPO with a price range of 170-230 pence per share.

Fazelbhoy did not return requests for comment. A spokesman for Topaz was not immediately available.

Renaissance bought Topaz through a share swap deal in 2005. Topaz made a profit of $70 million last year on revenue of $408 million. – Reuters