"As a result of the acquisition, Stan Kroenke has a beneficial interest in, and controls voting rights over 17,613 ordinary shares in the company, representing 28.3 per cent of the company's issued ordinary shares," a statement posted on Arsenal's official website said.
With a 25% stake in the Gunners, Uzbek-born Usmanov was previously the club's largest shareholder.
The move has sparked speculation that the American businessman is on the verge of a acquiring a 30% stake which would lead to a forced buyout, although Kroenke, who owns a number of U.S. sports teams, has indicated that he has no interest in a buyout.
Arsenal face Portsmouth in their Premier League match on Saturday. Russia's Andrei Arshavin, who has scored six goals and a similar number of assists in nine league games since arriving at the North London club in February, is expected to be in the starting line up.