One of Goldman Sachs' three global co-heads of prime broking is set to retire in the next few weeks as a shortage of cash has left prime brokers and their hedge fund clients struggling to make money.

Ravi Singh is set to retire in November, according to a source at Goldman Sachs, who said: "He has been head of Global Securities Services, which is what we call prime broking, since 2002 and has been with Goldman Sachs for 19 years. The business will continue to be led by Mitchell Lieberman in New York and James Paradise in London, the other global co-heads."