It looks like Tesla (TSLA 0.38%) can now count billionaire investor Jim Simons as a major shareholder (at least during Q4). According to a form 13G filing (similar to the 13F in that it discloses stock investments by large investors) by Simons' Renaissance Technologies, the hedge fund bought just under 3.3 million shares of the electric car, battery, and solar panel maker during the fourth quarter of 2019. 

Since the beginning of the fourth quarter, Tesla's shares have absolutely skyrocketed, gaining almost 250% in value. According to the filing, Renaissance Technologies held more than 3.9 million shares at the end of 2019. At recent market prices, that stake would be worth $3.3 billion. 

Man holds toy rocket as it begins to take off.

Image source: Getty Images.

The fund's Tesla position likely changed multiple times in Q4 (and since)

While it's possible that Renaissance Technologies kept Tesla in its $130 billion portfolio, it's highly unlikely it did so. This fund focuses on quantitative analysis, or as it describes, "...strictly adhering to mathematical and statistical methods", not fundamental analysis of companies for their business prospects. As a result, it tends to hold stocks for only a few days, on average. 

Based on that history, it's likely that the fund actively traded out of -- and back into and then out again -- Tesla shares multiple times during the fourth quarter, and that it's Tesla investment has change significantly in the two-plus months since the calendar turned to 2020. Add it all up, and while it's always interesting to see when notable investors invest in a high-interest stock like Tesla, Renaissance Technologies' strategy is not one that individual investors can replicate