(Bloomberg) -- President Donald Trump’s campaign burned through almost half of its cash in September, as his re-election effort cut back on advertising in some key battleground states and he lags in the polls behind his much better-funded Democratic adversary, Joe Biden.

The latest filing with the Federal Election Commission showed that Trump entered the final 34 days of the presidential election with $63.1 million in the bank, down from $121.1 million at the end of August, when his campaign began to scale back some television spending and even abandoned advertising in the key states of Pennsylvania and Michigan for a period.

Trump’s campaign committee raised $83.1 million in September while spending $139.3 million, the filings showed.

The campaign announced Thursday that his broader re-election effort, which includes the Republican National Committee and two joint fundraising committees, raised $247.8 million in September, but much of that money was earmarked for the RNC and state parties.

The September haul further puts Trump at a disadvantage with Biden and the Democratic National Committee, which raised $383 million in the month and say they have $432 million in the bank. The campaign and the DNC raised $748 million in August and September alone, about $290 million more than Trump over the same period. Biden’s campaign is to report its financial information to the FEC Tuesday.

Trump is being forced to play catch-up in fundraising at the same time he remains consistently behind Biden in national surveys. The president is now down 8.6 percentage points down in the RealClearPolitics polling average and behind, but by narrower margins, in key battleground states just two weeks before Election Day.

Small-dollar donors, those giving less than $200, provided 26% of the $68.4 million donated directly to the Trump campaign, though the president also raises money from them through the Trump Make America Great Again Committee.

In July, the last month that Trump out-raised Biden, the $36.5 that the committee transferred accounted for about half the campaign’s total receipts. But over the quarter, as the costs of raising money from grassroots donors increased, the amount of the transfers fell to $9.2 million in September. Overall in the third quarter, the committee spent $181 million to raise $235.7 million, or 77 cents for each dollar raised.

The high fundraising costs, which mostly went to digital advertising and acquiring lists of online contact information for potential donors, starved the campaign of needed cash. Under Federal Communications Commission rules, candidates get the lowest available rate for television ads within 60 days of an election. Biden’s campaign has booked $162 million in television ad time from Oct. 1 through the election, according to Advertising Analytics, while Trump has booked $79 million.

The Republican National Committee, which is helping with Trump’s voter mobilization efforts, raised $71.8 million in September, spent $108.6 million and ended September with $78.1 million cash on hand, its FEC filing shows.

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