Ray Dalio, founder of Bridgewater Associates, has retained his crown as the world's most successful hedge fund manager, according to an annual ranking by one of the longest-standing investors in the sector.

Dalio's Bridgewater Pure Alpha fund generated gains of $1bn in 2012, according to LCH Investments, keeping Dalio in the number one spot he took from George Soros in last year's rankings. The gains mean that since Dalio began running the fund in 1975 he has returned $36.8bn to investors.