Democrat Joe Biden's campaign and aligned Democratic Party committees entered September and the fall sprint to Election Day with US$466 million in cash reserves -- giving the former vice-president a significant financial advantage over U.S. President Donald Trump.

Team Biden's cash position, released by his campaign Sunday night, puts the Democratic nominee and his party about $141 million ahead of Trump's political operation. It represents a sharp reversal from the opening months of the general election when Trump enjoyed a formidable financial lead.

The New York Times first reported Biden's cash stockpile.

Heavy spending by Trump and record-breaking fundraising by Biden and his allies in August as he added California Sen. Kamala Harris to the ticket helped Democrats overtake the President and the Republican National Committee.

Trump and his joint operation with Republicans started September with $325 million in its cash stockpile, Trump campaign spokesman Tim Murtaugh announced on Twitter late last week.

The numbers released Sunday came as campaigns filed reports with federal regulators detailing their fundraising and spending during August.

The candidates' filings show that Biden outspent Trump by more than 2-to-1 in August, $130 million to Trump's $61 million. The president's campaign temporarily halted its advertising in key states last month as he struggled to gain traction in the polls.

That month, Biden spent $94.3 million to Trump's $55.7 million on advertising, according to Kantar's Campaign Media Analysis Group.

The new filings mark the first time in the campaign that Biden's political operation has built a larger financial stockpile than that of the president. At the end of March 2020, for instance, Trump and Republicans had a cash advantage over Biden and Democrats that exceeded $170 million.

But the president's fundraising edge began to evaporate over the early months of the summer as his campaign spent heavily on advertising and fundraising operations, and as Democratic donors coalesced around Biden's candidacy.

Liberal donor enthusiasm also has spilled into other contests and political fights. This weekend, donations to Democratic candidates and causes via the online fundraising platform ActBlue surged past $100 million, following the death of Supreme Court Justice Ruth Bader Ginsburg.

Facing a potential cash crunch, Trump earlier this month pledged to spend "whatever it takes" of his own branding and real-estate fortune to win reelection. But he's also had additional outside help.

A new pro-Trump super PAC, called Preserve America, reported Sunday that it already has spent more than $51 million to oppose Biden. Its funders include casino billionaire and staunch Trump supporter Sheldon Adelson and Home Depot co-founder Bernie Marcus.

Sunday's filings show Adelson also is spending heavily to help vulnerable Republicans in the Senate. Democrats need a net gain of just three seats to flip the chamber if they also capture the White House or four if Trump wins reelection.

Adelson and his wife Miriam contributed a combined $25 million in August to the Senate Leadership Fund, a super PAC aligned with Senate Majority Leader Mitch McConnell, a Kentucky Republican.

The Adelson donations accounted for about two-thirds of the $37.4 million raised by the group in August.

Biden also is benefiting from spending by the super-wealthy. Former New York City Mayor Michael Bloomberg recently announced he would spend at least $100 million in Florida to assist Biden in that crucial battleground state.

Both candidates plan to bombard the airwaves in the weeks ahead.

The Biden campaign has about $116 million booked through Election Day, and the Trump campaign has about $125 million, Kantar/CMAG figures show.