a couple of weeks ago, Sheldon Adelson was frustrated with Donald Trump’s “lack of focus” and misdirected attacks at fellow Republicans. However, the Las Vegas casino billionaire appears to have changed his tune, committing $25m to an anti-Hilary Clinton super PAC, Future 45.

The cash infusion expects to finance ads in the final week of the campaign hitting the Democratic nominee for alleged corruption, Fox News reported on Monday.

Launched by the Ricketts family in Chicago, the pro-Trump group has recently been comparing Clinton to Richard Nixon, referring to her as a “secretive, paranoid politician who destroyed 30,000 pieces of evidence”.

Two senior Republican sources familiar with the donation described it to Fox News as a “massive” amount of money to be spent during the final week of the presidential race.

Adelson, who has remained largely on the sidelines until now, had previously said he would give $100m to help Republican nominee Trump with the race for Presidency. However, according to two allies of the casino owner, he was concerned with the candidate’s political gaffes, incendiary rhetoric, mixed poll numbers and other issues.

Fox News’ Ed Henry described the infusion of money as the “floor” and not a “ceiling”, reporting “there’s more money coming”. Republican sources told the cable news station that Adelson may donate an additional $25m into races for the White House, Senate and House of Representatives in the upcoming days.

As well as the WikiLeaks email scandal casting doubt over Hilary Clinton’s campaign, Henry believes the $25m “would give confidence to other donors who have been on the sidelines”.