But Biden and the DNC outraised Trump and the RNC in March. The DNC, buoyed by an $18 million transfer from billionaire Mike Bloomberg's campaign that sparked a campaign finance complaint, brought in $32.7 million in March to the RNC's $24 million. Trump's campaign has yet to file its March financial report, but Republicans had previously said that Trump, the RNC and affiliated fundraising committees raised $63 million in March, less than the combined $79.4 million raised by Biden and the DNC.

It's unclear if Biden's financial surge will continue at the same pace in the long term, though. Biden said in the March 15 Democratic debate against Bernie Sanders that he had raised $33 million to date that month, meaning his fundraising tailed off in the second half of March, as the coronavirus pandemic prompted stay-at-home orders, mass unemployment and other large-scale economic disruptions, while also shutting down public campaign events.

The Biden campaign has since shifted to holding online events. But Biden noted in an email to supporters Monday night that the pandemic may well hamper his campaign's finances this month and beyond.

"I know that April may not match March in fundraising, and that's okay by me," Biden wrote in an email to supporters. "The world has changed a great deal. It's unrecognizable at times. Your family and your community need your generosity and strength now more than ever."