UBS named John Holland and Martina Slowey as co-heads of European prime brokerage. Holland most recently served as global chief operating officer of the bank's cash-equities business. Slowey was global head of prime-brokerage sales, a role she will retain.

The Wall Street Journal reports that both will be based in London and will serve as replacements for Robert Munro, who went on sabbatical in April.

In recent years, UBS has sought to penetrate the lucrative business of providing trading and lending services to hedge funds that has long been dominated by firms like Goldman Sachs and Morgan Stanley. A critical early step was the hiring of Alexander Ehrlich from Goldman in 2003 as global head of prime brokerage.

While UBS’s prime-brokerage business has gained market share, write-downs at the corporate level could hamper its ability to expand further. Even after writing off approximately $18 billion from its holdings in sub-prime mortgages and other risky securities, some analysts believe UBS has more remaining sub-prime exposure than any other European bank.

A recent survey conducted by research firm Celent indicates that hedge funds are looking for ways to reduce their reliance on prime brokers as a way of reducing costs.