Usmanov's Red & White vehicle - which he jointly owns along with business associate Farhad Moshiri - said on Friday that it had raised its holding in Arsenal to 28 percent from 27 percent.
The Red & White vehicle has been steadily building up its stake in Arsenal over the course of the week, as part of Usmanov's opposition to American businessman Kroenke's takeover of Arsenal.
Last month, Kroenke agreed a deal with Arsenal's main shareholders and executive management to take over the club and acquire a majority shareholding in Arsenal.
Kroenke controls around 64 percent of Arsenal and he has been legally obliged, under British takeover rules, to make an offer for the remaining shares.
Kroenke has offered 11,750 pounds per share but Usmanov has made a rival offer of 14,000 pounds per share.
The 63-year-old Kroenke, worth $2.9 billion in 2010 according to Forbes, already owns several U.S. sports teams including the NBA's Denver Nuggets, the NHL's Colorado Avalanche, the NFL's St Louis Rams and Major League Soccer's Colorado Rapids.
Arsenal is one of England's most successful teams but the club has not won a trophy since claiming the FA Cup in 2005, and many of its fans have urged French manager Arsene Wenger to spend more money on signing up top players.
