Crispin Odey, one of Britain's highest-profile hedge fund managers and political donors, has been charged with indecent assault.
He is alleged to have assaulted a woman over the age of 16, at an address in Chelsea in July 1998, the Crown Prosecution Service said.
Mr Odey, a backer of Brexit and Boris Johnson, was charged on 14 May,
In a short statement, Mr Odey said: "The allegation is denied and I will strongly contest this matter."
The latest Sunday Times Rich List says Mr Odey, 61, and his wife are worth £825m.
Mr Odey established Odey Asset Management in 1991. He went to Harrow School and then studied History and Economics at Christ Church, Oxford.
He owns a home in Swan Walk, Chelsea, a Thames riverside street in Chelsea.
In the run up to the 2016 European Union referendum, Mr Odey donated more than £870,000 to pro-Brexit groups.
He has also made the headlines in the past for spending about £150,000 on a Palladian-style stone temple to shelter chickens at his Gloucestershire mansion.