He denied assaulting a woman aged 26 at the time of the alleged incident in 1998.
A district judge ruled the allegations against him were unproven.
District judge Nicholas Rimmer said there were "inconsistencies" in the allegations of Mr Odey's accuser.
Mr Odey admitted that he had propositioned the woman while she visiting his flat in Chelsea but denied touching her.
The wealthy investment manager has been a major donor to the Conservative Party and established Odey Asset Management in 1991. He was a major supporter of the Brexit campaign.
He has been a regular speaker at fund industry events for a number of years.