First Gulf Bank's most senior investment banker and its head of global markets sales have both left their positions at Abu Dhabi's largest bank by market value, sources aware of the matter told Reuters on Tuesday.

The pair join the bank's head of treasury, Christopher Wilmot, whose departure was confirmed to Reuters earlier in the day.

Simon Penney, head of wholesale and international banking at FGB, has resigned after less than three years with the lender to return to Britain, three sources with knowledge of the matter told Reuters.

The sources also noted that Adrian Hodges, head of global markets sales at FGB, left the bank in March, with one of the sources saying it was for personal reasons.

An FGB spokesman declined to comment on Penney's status at the bank, but confirmed Hodges' departure.

Banks have been squeezed by the lower oil price environment, and a number of lenders have laid off staff or seen others leave of their own accord.

Penney joined from Royal Bank of Scotland and was tasked with building up the bank's investment banking business.

A number of Gulf banks sought to develop such capabilities in the last couple of years by hiring executives from international lenders.

By doing so, they aimed to diversify their revenue streams and improve earnings at a time when bountiful liquidity among regional banks restricted earnings from traditional lending and deposit-taking.

FGB cut close to 100 jobs in November, which sources told Reuters at the time included the corporate and investment banking teams and was part of efficiency savings.

Controlled by the Abu Dhabi ruling family, FGB reported a 6 per cent drop in net profit in the first quarter of 2016, citing lower fee income for the year-on-year decline in earnings.-Reuters