While the latest stock market upsurge turned Micron (NASDAQ: MU) into a household name, Jim Simons made a prodigious investment in the memory company as far back as 2013 – when it was trading at approximately $18 – and saw the equity rise almost exactly 5,000% since.
Over the years, the billionaire’s Renaissance Technologies made multiple adjustments to the position, meaning he did not see the entire return from the initial bet, but given MU shares, performance in recent months, he is nonetheless significantly ‘in the money.’
Specifically, Jim Simons increased his investment in Micron by 151% in the fourth quarter (Q4) of 2025 by acquiring nearly $660 million worth of the stock. At the time, the memory giant was trading in the range between approximately $180 and $300.
At press time on May 29, and after a 223.58% year-to-date (YTD) rally, MU is changing hands at $923.52. Therefore, the position reported as worth $859 million at the end of 2025 would have risen to $2.77 billion in just five months had the investor not reduced the stake by 21% in Q1.
Still, the subsequent 13-F filing – the one covering Q1 2026 – shows that Micron was Simons’ fifth-largest portfolio holding, and Finbold decided to examine the billionaire’s fortunes with the largest four positions.
Jim Simons’ Kinross Gold stock investment
Renaissance Technologies first began developing its fourth-largest – as of the most recent filing – position, Kinross Gold Corp (NYSE: KGC), as far back as 2013, when the shares were trading at roughly $5.82.
In the fund’s typical fashion, there were multiple balance changes, and the most recent substantial purchase that was not succeeded by a comparable sale came during the first three months of 2026 at an average quarterly price of $34.02.
Considering that KCG stock is, at press time on May 29, changing hands at $29.29, Simons could be up 403% relative to the initial buy, but might be 14% in the red on the most recent purchase.
Jim Simons’ Apple stock investment
The situation would have been significantly better regarding the third-largest portfolio position – Apple (NASDAQ: AAPL) – had the billionaire held the original, 2013 stake, likely acquired at an average price of $15.38.
Indeed, AAPL shares have rallied 1,920% to $310.66 since then, but, notably, Simons reestablished the holding only in Q1 2026 – after clearing it during the previous year – at approximately $260.16, indicating he is still in the green, albeit by a relatively limited 19.41%.
Jim Simons’ Palantir stock investment
Thanks to the extensive trading and its relative recency, the performance of Renaissance Technologies’ Palantir (NASDAQ: PLTR) is somewhat more difficult to gauge, though it is evident the billionaire has profited overall from the bet on the firm, given it was, at the end of Q1 2026, the second-biggest portfolio holding.
Jim Simons made his first PLTR purchases at roughly $24 toward the middle of 2021, and his most recent significant buy was at about $180.80 and executed during the final three months of the previous year.
Palantir shares themselves are, at press time on May 29, changing hands at $146.77, meaning they soared 511% relative to the taking of the original position but fell 18.82% relative to the most recent known buys.
Jim Simons’ United Therapeutics stock investment
Lastly, Jim Simons largest stock position – accounting for 1.7% of the 3,213-stock portfolio relative to Micron’s 1.1% – is undeniably up compared to the original likely average purchase price of $64.42 in 2013 and the most recent, Q3 2025, of $335.18.
Indeed, having risen 13.16% year-to-date (YTD) to $565.50, United Therapeutics Corp (NASDAQ: UTHR) is 777.83% above the value at the time the original stake was built, and 68.72% above where it stood during the latest increase.
Featured image via Shutterstock
