Renaissance Technologies, added more than 3 million shares of Tesla to its holdings in the fourth quarter of last year, as the electric-vehicle maker’s shares catapulted higher, according to public filings.

The hedge fund founded by James Simons, considered the premiere quantitative-driven investor, owned 3.9 million shares of Tesla at the end of Dec. 31, with the company’s stake in Renaissance’s portfolio jumping from 0.1% in the prior quarterly period to 1.3%, according to file-tracking site Whalewisdom.

The purchases would have come as Tesla’s shares TSLA, +7.34% were zooming higher, punishing a number of investors with short positions who had bet that the Elon Musk-run Silicon Valley darling would see its price collapse soon. Instead, Tesla’s shares have surged 142% in the past three months and has more than doubled since the beginning of 2020, according to FactSet data.

By comparison, the Dow Jones Industrial Average DJIA, -0.53% has gained 4.2% over a three-month period, and 2.4% so far this year, while the S&P 500 index SPX, -0.26% has climbed 7.9% in the past three months and 4.2% in the year to date. The technology-laden Nasdaq Composite COMP, +0.06%  has advanced nearly 14% in the past three months and boasts a 8.3% gain in 2020 so far.

By some reckonings, Simons is one of the most famous quantitative traders ever. He retired from the firm’s day-to-day operations of Renaissance a decade ago, but is still involved with the firm.

For his efforts, he ranks No. 21 on the Forbes list of the wealthy, with a net worth of $21.6 billion.

Renaissance’s main investment offering is the flagship Medallion Fund, which has generated a 39% average annual return from 1988 to 2018, that is despite rich fees, which currently include a 5% management and 44% performance fees.

Those costs haven’t prevented Medallion from outperforming Warren Buffett’s Berkshire Hathaway BRK.A, +0.06% BRK.B, +0.01%  over the same 30-year period writes Nick Maggiulli of Ritholtz Wealth Management.

The Medallion Fund limits its assets to roughly $10 billion and is only available to Renaissance employees.

For its part, Tesla completed a $2 billion secondary offering on Friday and analysts have continued to hold a bullish view on the company. Bernstein analyst Toni Sacconaghi nearly doubled his price target, describing the vehicle maker as the “ultimate ‘possibility’ stock.” Sacconaghi raised his price target to $730, which was still below current levels at $845, from $325. “Revenue in 2020 is expected to rise by 30.3% to approximately $32 billion, and earnings are forecast to rise to $8.68 per share from $0.20 per share in 2019,” Whalewisdom researchers wrote.

Beyond Renaissance Tech, JPMorgan Chase & Co. JPM, -1.21% was seen purchasing roughly 2.2 million shares of Tesla in the most recent period, bringing its position to 2.5 million, according to Whalewisdom data.