Want to start a hedge fund? It's hard. With even the biggest, well-established names in the industry having to send apologies to investors because of poor performance, attracting money to a new firm is a challenge.

In the early 2000s, a series of hedge funds launched, often built around a single trader with a successful strategy. Some of these quickly attracted billions - Brevan Howard launched its first fund in 2003 and attracted $3.7 billion in its first year - and have now built themselves into firms with the sophisticated risk-controls and other functions needed to attract institutional money.