American-Jewish billionaire and philanthropist Sheldon Adelson has reportedly donated $25 million to a super PAC dedicated to defeating Hillary Clinton's campaign for the presidency, Fox News reported.

Adelson had previously expressed frustration over the campaign of Republican Candidate Donald Trump, whom Adelson thought suffered from a "lack of focus" and had little chance of beating Clinton.

Adelson appears to have had a change of heart after the FBI announced that it would reopen its investigation into Hillary Clinton's use of an illegal private email server as Secretary of State. Trump had been narrowing Clinton's lead in the polls even before the FBI's announcement.

Adelson's "massive" donation was reportedly given to super-PAC Future 45, which has run ads comparing Clinton's corruption with that of former President Richard Nixon, who resigned from the presidency in disgrace.