(Bloomberg) -- Ray Dalio’s Bridgewater Associates and Jim Simons’ Renaissance Technologies beat their rivals in a tough year for hedge funds in 2018, making a combined $13 billion for their investors.

The profits accounted for more than half the money generated by the top 20 managers last year, according to estimates by LCH Investments NV, a fund of hedge funds. Firms outside that top group lost more than $64 billion as stock declines and volatility took their toll.

“Most managers in the top 20 either managed to stay out of trouble when equity markets fell sharply toward year-end, or had an investment approach that was not linked to the direction of equity markets,” said Rick Sopher, chairman of LCH.

Both Bridgewater and Renaissance are well-diversified funds that can benefit from rising and falling stocks. The industry as a whole put in its worst performance last year since 2011, with several big names including T. Boone Pickens exiting the market.

Bridgewater also topped LCH’s annual rankings of managers by their overall profits since inception, a listing where the largest and oldest hedge funds tend to do best. Renaissance was one of two new entries to the list, along with Two Sigma.

Top 20 Managers Ranked by Profits Since Launch

Gains are in billions of dollars
* Through Dec. 31, 2017

Source: LCH, eVestment

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