In this June 30, 2019, file photo, US Ambassador to Israel David Friedman (left) speaks with US businessman and philanthropist Sheldon Adelson (center) and his wife, Miriam, at the City of David archaeological and tourist site in east Jerusalem.
CNN  — 

Billionaire casino mogul Sheldon Adelson and his physician wife, Miriam, poured a whopping $75 million into a super PAC launched in late August to aid President Donald Trump’s reelection, new filings show.

The couple’s donations to Preserve America PAC, delivered in several installments in August and September, account for nearly $9 out of every $10 the political action committee raised through September 30, according to its first report with the Federal Election Commission.

Other donors include Home Depot co-founder Bernard Marcus, who contributed $5 million, and Wisconsin roofing magnate Diane Hendricks, who gave $1 million. In all, the group has raised nearly $83.8 million.

The PAC’s heavy spending on Trump’s behalf in key battleground states is aimed at providing last-minute help to the President as his Democratic rival, Joe Biden, raises enormous sums from an enthusiastic liberal donor base and leads Trump in the polls.

This week, Biden announced that his campaign and its shared Democratic Party committees had collected $383 million in September, setting fundraising records for the second month in a row. The former vice president started October and the final, full month of campaigning with $432 million remaining in the bank, according to campaign manager Jen O’Malley Dillon.

Trump’s campaign, the Republican National Committee and their joint fundraising committees raised nearly $248 million in September, and Trump has $251 million in cash on hand. The President also lagged behind Biden’s political operation in fundraising and cash reserves at the end of August.

Despite the last-minute infusion from the Adelson-funded PAC, Biden and his supporters have dominated the airwaves in recent weeks. Pro-Biden ad spending on television hit $102 million over the past two weeks, compared with $61 million in pro-Trump spending, according to an analysis by the Wesleyan Media Project and the nonpartisan Center for Responsive Politics.

The Las Vegas-based Adelsons also backed Trump’s candidacy four years ago. In 2018, Trump bestowed the Presidential Medal of Freedom – the country’s highest civilian honor – on Miriam Adelson, citing her philanthropic work.

Preserve America has spent nearly $77 million through this week on its anti-Biden campaign, Federal Election Commission records show.

CNN’s Ryan Nobles and DJ Judd contributed to this report.