Investors are dealing with pain this year, but Jim Simons and Renaissance Technologies LLC are racking up such huge gains that 2020 could be one of the hedge-fund firm’s best years ever.

The Long Island-based firm‘s flagship Medallion hedge fund has risen 24% this year through April 14, according to investors. The performance is thanks in part to a 9.9% gain in March, a brutal month for global stock markets. Medallion’s gains come even after its hefty investor fees, which include a cut of 36% or more of all trading gains and 5% of all money invested in the fund.

Medallion is only open to employees, former employees and a handful of people close to the firm. Because employees are the firm’s owners, most of the fees end up going back to them in some form. Before those investor fees, Medallion, which manages nearly $10 billion, was up about 39% for the year on April 14.

Funds that Renaissance makes available to outside investors haven’t done nearly as well as well, however, though they have rebounded lately. The Renaissance Institutional Equities Fund (RIEF), for example, was down 10.4% through April 10, investors say. RIEF has a longer holding period than Medallion. The fund focuses on U.S. shares and aims for returns that more closely track the overall market.

By comparison, the S&P 500 index has fallen 11.4% this year, through April 14, while Vanguard’s 60/40 index fell 5.9%, in line with the performance of the average hedge fund, according to industry tracker HFR. Hedge funds aim to protect investors in times of crisis but few have performed like Medallion.