Oleg Deripaska, the owner of Russia's biggest aluminium maker, has acquired a stake in General Motors of just under 5 per cent, say two people with direct knowledge of the matter.
The Russian tycoon's stake in the world's largest car company, worth more than $900m at Tuesday's share price, is said to be a personal investment and unrelated to Gaz, the vehicle manufacturer he controls.
Mr Deripaska, named Russia's second-richest man by Forbes magazine, acquired the shares last year.
"He has a stake in GM which he acquired some time ago," said one of the people, who declined to be identified.
"It's a strategic investment on his part and unrelated to Basic Element [Mr Deripaska's holding company]."
The investment has not been discussed officially within Gaz's management.
Renee Rashid-Merem, a spokeswoman for GM, said the US carmaker did not comment on its stockholders.
However, she said that there had been no relevant filing to the US Securities and Exchange Commission, which would be required for any investor seeking to buy 5 per cent or more of GM. Basic Element declined to comment.
Mr Deripaska owns the aluminium giant, United Company Rusal, and recently invested $1.54bn in a large stake of Magna, the Canadian car parts and vehicle assembly company.
News of his GM investment is likely to excite speculation about the carmaker, which is in the middle of restructuring but last month reported unexpectedly strong quarterly earnings.
GM's highest-profile minority shareholder recently was billionaire Kirk Kerkorian, whose Tracinda Corp at one point owned nearly 10 per cent of the company.
Tracinda prodded GM to hold talks on a possible alliance with Renault and Nissan, a move the US carmaker's management rejected. Tracinda has since sold its GM shares.
Gaz is seen as one of the developing world's most ambitious carmakers, and its name has been linked to Ford Motor's efforts to sell Jaguar, Land Rover and Volvo, its three premium brands, as it was to DaimlerChrysler's sale of Chrysler.
However, Gaz has denied any interest in Jaguar or Land Rover. Its primary business is commercial vehicles, of which it is Russia's dominant producer.
Reports that Mr Deripaska was seeking to build a stake in GM surfaced last year.
At the time, he denied he planned to amass a large stake in the company.
