Auditors Moore Stephens were called in after the Sunday Times newspaper in July said secret payments had been made to an executive on the Olympic Park Legacy Company (OPLC), the body responsible for finding tenants for the venues after the Games.
The OPLC board last February unanimously chose West Ham, later relegated from the Premier League, as preferred bidder to take over the new 486 million pound stadium in east London ahead of city rivals Tottenham Hotspur.
The newspaper said the OPLC's corporate services director Dionne Knight had been paid 20,000 pounds by West Ham for consultancy work before and after the decision was made.
West Ham said Knight's work was in relation to the procurement of a construction partner after the Olympics.
Knight, who had disclosed a personal relationship with West Ham director Ian Tompkins when she started at the OPLC, was suspended and the OPLC appointed the auditors to review its own internal stadium procedures.
Moore Stephens found there was no evidence to suggest Knight had access to or had passed on confidential information about the stadium process, or that she influenced the selection, the OPLC said in a statement.
The OPLC added that its founder members, the Mayor of London and the government, "concluded that there are no grounds for re-considering their decision to select West Ham United FC and the London Borough of Newham as Preferred Bidder".
West Ham plan to retain the athletics track in the stadium and reduce the capacity to 60,000 from 80,000 before moving in for the 2014/15 season.
West Ham are not out of the woods yet. Tottenham, which planned to remove the track and build a new purpose-built soccer stadium, is pursuing a judicial review of the OPLC's initial decision in the High Court in London.
An oral hearing is scheduled for Wednesday, August 24.
The court has previously rejected legal moves from both Tottenham and Leyton Orient, a third-tier club based near the stadium in east London, who fear they could lose fans.
London 2012 officials feel keeping the athletics track is crucial to offering a sporting legacy which they promised the International Olympic Committee would happen after the Games.
A London bid for the 2017 athletics World Championships largely hinges on the track being kept in the Olympic stadium.
