Citadel founder and CEO Kenneth Griffin earned $1.7 billion in 2015. Getty Images/Larry Busacca

Hedge funds aren't riding high as they once were, but their managers remain the most richly compensated individuals in the nation.

As the broader hedge fund industry faces a crisis of confidence, top hedge fund leaders continue to rake in massive returns, with the top 25 managers making a combined $13 billion in 2015, according to an annual ranking published by Institutional Investor’s Alpha magazine.

Though just over half of the record $25.3 billion that managers made in 2009, the total exceeds 2014’s sum of $11.6 billion. Five of these managers made earnings of more than $1 billion each.

For the second year running, Kenneth Griffin of Citadel topped the list, a spot he shared with James Simons of Renaissance Technologies. Each earned $1.7 billion.

Simons and Griffin both run hedge funds focused on quantitative analysis and bespoke high-frequency strategies, underscoring the success of such firms in an otherwise difficult trading environment in 2015. Four of the top 10 managers ran quantitative firms, a group that includes John Overbeck and David Seigel of Two Sigma Advisors.

In the second half of last year, many hedge fund giants were battered by volatile markets and implosions at companies beloved by money managers — notably Valeant Pharmaceuticals, whose 75 percent decline stung top managers like Bill Ackman and John Paulson. Roughly half of the 10,000-plus hedge funds operating today lost money last year.

But other investors managed to steer safely through the turbulent markets. Ray Dalio, chief executive of Bridgewater Associates, earned $1.4 billion after his main fund delivered returns of 9.9 percent in 2015. David Tepper made the same amount after his $18 billion Appaloosa fund returned 11 percent over the course of the year.