United also remain ranked as the most valuable team in any sport, worth €1.7bn, more than baseball’s New York Yankees and the NFL’s Dallas Cowboys.
Arsenal are fourth on the list, worth €986m, behind Real Madrid (€1.4bn) and Barcelona (€999m) but just ahead of Bayern Munich (€943m).
The Forbes list ranks Chelsea in seventh place, worth €581m, and Liverpool eighth with a value of €472m.
United’s huge global fanbase, estimated by Forbes to number 330 million, has helped maintain the club’s position at the top. However both Real Madrid and Barcelona have higher revenues than United, due in large part to the fact they have negotiated their own individual television rights deals for Spanish football.
The figures are also based on last year’s financial results and reflect United getting to the Champions League final. This season Alex Ferguson’s side failed to make the knockout stage and their income from European football is expected to suffer a corresponding drop, especially in relation to Real Madrid and Barcelona who are both in the Champions League semi-finals.
Meanwhile United have ruled out the prospect of joining the expanding NextGen European U19 league.
Arsenal and Chelsea have confirmed they will participate next season, when the league expands from 16 to 24 teams.
It takes to seven the number of British teams involved and means United are the only member of England’s elite not to commit to the event given Manchester City, Liverpool and Tottenham were all involved in the debut season.
And despite the obvious attraction of having United featuring alongside Barcelona and Inter Milan, who beat Ajax in this season’s final, and the added competition for their U19 group, the Irish Examiner understands the Old Trafford hierarchy have already decided not to get involved.
United will continue to look for extra competition away from domestic fare, though, and earlier this month had a successful run to the final of the Dallas Super Cup, where they were beaten by Brazilian outfit Coritiba 2-1, after having two men sent off.