Alisher Usmanov has increased his stake in Arsenal to 21 per cent.
The purchase, which was announced to the Stock Exchange on Tuesday morning, makes Usmanov's company the club's second-highest shareholder behind Danny Fiszman, who has 24%.
Usmanov, who formed the company alongside fellow investor Farhad Moshiri specifically to hold equity in the north London club, first bought into Arsenal when he paid former vice-chairman David Dein around £75million for his 14.65% holding in August.
Dein left the club in April over differences with the board over investment possibilities - with American businessman Stan Kroenke's potential involvement thought to be the main sticking point.
But Dein is the chairman of Red and White Holdings Ltd and looks certain to remain a key figure as the debate over the Gunners' future continues.