Russia-based billionaire Alisher Usmanov has upped his stake in Arsenal to "over 27%".
Red & White Holdings Limited - which is jointly owned by the Usbek oil magnate and Farhad Moshiri - made the brief announcement today, but did not give any details as to the additional stock acquired.
American Stan Kroenke remains the largest individual shareholder in the club, with 29.9%.
Under the strict financial rules of the City, were any party to cross the 29.99% takeover threshold, they he would be obliged to make a formal offer for the remainder of the shares.
The news Usmanov - who unlike Kroenke does not yet have a seat on the Arsenal board - has continued his steady accumulation will add further speculation that the Gunners, currently the only one of the 'big five' not in foreign ownership, are set for more changes behind the scenes.
However, during April 2010, the Red & White group released a statement maintaining that a full-blown offer was not on their agenda and they remained "a committed long-term investor in Arsenal".
Former director Lady Nina Bracewell-Smith put her family's 15.9% stake up for sale in April, and these latest dealings could be the result of some minor tradings.
Non-executive director Danny Fiszman, who controls 16% of shares, is the club's other major shareholder.
Usmanov has long called for Arsenal to invest heavily in the team, but in 2009 saw his proposed rights issue to generate new cash turned down in favour of the status quo which sees the Emirates Stadium club remain self-financing as they bid to end six years without a trophy.
Red & White Holdings had argued the scheme would help to reduce both the long-term debt of some £400 million, which is mainly associated with the new stadium, and also hand manager Arsene Wenger extra transfer funds.
In the six months to November 30, 2010, Arsenal announced an overall loss of £2.5 million, but their football-related profit is £9.3 million, compared to £18 million for the same period a year before.
On the pitch, Wenger's men have endured a testing few weeks which saw them suffer a shock Carling Cup final defeat to Birmingham at Wembley, before then crashing out of Europe in Barcelona and the FA Cup at Manchester United.
Heading into the international break, Arsenal trail Premier League leaders United by five points, but hold a game in hand.
However, should the Gunners win all of their remaining nine league fixtures, which include a trip to north London rivals Tottenham before a May 1 showdown with United, then they will be champions.