The total, up from US$61.7 million in April, was disclosed as Trump prepared for Saturday's smaller-than-expected rally in Tulsa, Oklahoma, his first major campaign event since the coronavirus pandemic shut down most campaigning.
Former Vice President Biden has stepped up fundraising in recent months since becoming the Democratic Party's de facto nominee for the Nov. 3 presidential election.
He has also built a lead over Trump in national opinion polls amid the twin crises of the pandemic and civil unrest over police brutality in many US cities.
In May, Biden and the Democratic National Committee raised US$80.8 million, their largest single month of fundraising.
Trump, however, continued to have a cash advantage over Biden, according to disclosures filed separately by the two campaigns on Saturday.
The president has been campaigning for re-election since 2017 and his campaign had US$108.1 million in cash on hand at the end of May. Biden, who launched his campaign in April, had US$82.4 million.
Trump's campaign also spent more than twice as much as Biden's campaign did in May, shelling out US$24.5 million with over half of that going to political advertising. Trump's campaign also spent about a half million dollars on legal expenses during the month, slightly lower than its outlays on lawyers in April.
Biden's campaign spent US$11.7 million in May. The candidate only this week announced his first major advertising blitz, launching US$15 million in TV and digital ads in the crucial states of Pennsylvania, Michigan, Wisconsin, Arizona, Florida and North Carolina, all states Trump won in 2016.
