On Tuesday, the Institutional Investor’s Alpha magazine revealed the 25 best paid hedge fund managers in 2016, a year that was quite trying for most in the industry. And it was James Simons, the founder of camera-shy quant hedge fund, Renaissance Technologies, that topped the list. Simons, a former codebreaker for the National Security Agency with a Ph.D. in mathematics, earned $1.6 billion in 2016. That’s enough to cover the market capitalization of department store chain, J.C. Penney, valued at $1.4 billion. According to the Bloomberg Billionaire’s Index, Simons is worth about $15.7 billion.

It’s a shift from nine years ago, when the best paid hedge funder was an activist investor who had lived and breathed finance for most of his career. That was John Paulson, who made a name for himself by betting against sub-prime mortgages ahead of the financial crisis. For that, he earned $3.7 billion. But today, his fund, which once grew as large as $36 billion under management in 2011, has dwindled to $10 billion, following double-digit losses on wrong-footed bets on drug companies in 2016. Part of those losses were also likely due to investors pulling their funding out after losing confidence in Paulson.

That comes as, increasingly, investors are growing wary of the industry’s pricey fees and unsteady returns, when there are cheaper index funds that do a better job. As a result, many hedge funds have recently begun to cut their hefty management fees of about 1-2%, and a 20% cut of profits. Even Paulson remarked back in 2014, when he still commanded $22 billion, that he felt the same pressure.

Yet Renaissance Technologies, which invests using computer algorithms and quantitative strategies, has seemed impervious to these pressures. Its flagship fund, the Medallion fund, is known to charge much higher: a 5% management fee, and 44% cut of the profits. And investors were willing to pay for it. While many other funds suffered outflows in 2016, The Wall Street Journal, citing unnamed sources, reports that Renaissance attracted over $7 billion in new money during the year. Now, the firm is said to manage about $42 billion, with Medallion enjoying average annual returns of 40% since 1988. Still, Simons was paid roughly $100 million less than the year prior.

Meanwhile, as investors are falling out of love with the traditional hedge fund, major hedge funds are also turning to quantitative investing. Paul Tudor Jones, for example, has recently introduced computer-driven tools that would imitate trades from his firm’s best managers.