A Tesla Model 3 car is on display during the Auto China 2018 at China International Exhibition Center on April 25, 2018 in Beijing, China.

Tesla shareholder Baillie Gifford & Co. has just increased its stake in the electric car maker, according to a regulatory filing Friday.

The U.K.-based investment management firm, Tesla's second-largest institutional shareholder, bought 108,931 of the company's shares during the fourth quarter, according to the filing and data compiled by FactSet.

It now owns just over 13.2 million shares valued at roughly $4 billion. Its stake increased from 7.64 percent at the end of the third quarter to 7.71 percent as of Dec. 31.