Updated Wednesday at 2:15 p.m.

As more 2020 Democrats report their fundraising totals, Vermont Sen. Bernie Sanders remains ahead in the cash race with the $18.2 million he received from more than 500,000 donors since he entered the presidential campaign in February.

Former Texas Rep. Beto O'Rourke reported Tuesday raising a total of $9.4 million in the 18 days between his campaign launch and the end of the first quarter. He is working to challenge Sanders' dominance of the liberal grassroots after pulling in $6.1 million in his first day, topping Sanders' one-day total of $5.9 million.

California Sen. Kamala Harris and South Bend, Ind., Mayor Pete Buttigieg have also reported impressive totals for the first quarter of the year, which ended on Sunday. Harris has raised $12 million, while Buttigieg, largely unknown before his presidential campaign announcement, has taken in $7 million.

The O'Rourke campaign is touting its per day fundraising — $520,000 per day since getting in, versus Sanders, who has raised $444,000 per day in the 41 days since getting in. Spliced another way, though, taking out the big Day 1 for both candidates, Sanders has raised about $307,000 per day compared with $194,000 per day for O'Rourke.

Either way, early on, all appear to be fundraising juggernauts. Including their first-day totals, Harris has raised $171,000 per day, and Buttigieg has taken in $107,000 per day.

Sen. Amy Klobuchar of Minnesota and former Colorado Gov. John Hickenlooper each said they raised $1 million in 24 hours. Another candidate to watch is Sen. Elizabeth Warren of Massachusetts, one of the biggest names running, who raised a relatively modest sum of $300,000 on her first partial day in the race.

The first quarter ended March 31, but campaigns aren't required to report their totals to the Federal Election Commission until April 15.

By the end of 2018, the Trump campaign had raised $67.5 million and spent $55.9 million. (The Trump campaign had raised about $28 million from individual contributions.) Two additional political action committees that function as joint fundraising committees with the Republican National Committee, Trump Victory and Trump Make America Great Again Committee, had raised an additional $100 million.

But the Trump campaign had only about $19 million cash on hand. Part of that is because of the number of rallies he has been holding. Before the midterm elections, for example, as NPR's Peter Overby reported, the Trump campaign held 18 rallies in 20 days campaigning for Republican Senate candidates.

The campaign also racked up some $6 million in legal bills, with most of it going to "defense attorneys in cases including Trump's alleged affair with porn star Stormy Daniels, Donald Trump Jr.'s meeting with Russians at Trump Tower and several allegations involving Trump's son-in-law, Jared Kushner," Overby reported.

Sanders has $28 million cash on hand, including $14 million the campaign started with. Sanders famously touted during the 2016 race that his average donation was $27. In this bid, it's less — $20. The campaign added that 88 percent of donations were under $200, and a majority of donors were younger than 39 years old.

Sanders' campaign said it has accumulated a total of almost 900,000 contributions in 41 days; a total, it says, that took 146 days to reach in his 2016 bid. Of 525,000 individual contributors, roughly 20 percent, or a little over 100,000, are new donors. Sanders has taken the unique step of setting up the ability for donors to make automatic payments to the campaign.

Harris said she had 218,000 contributions; 98 percent were under $100; and the average donation to her campaign was $55. While many Democratic candidates have eschewed raising money in traditional donor circles, Harris has not. She has spent years courting California's donor class, though her campaign says less than 1 percent of her donors cut checks for the maximum $2,800.

Buttigieg, who has seen his name recognition and favorability spike in recent days, said he has had 158,550 donors, with an average donation of $36.35, and almost two-thirds of the money raised was from donations of under $200.

"This is a big deal, I've got to tell you," Buttigieg said, explaining the numbers in a Facebook video. "This is way ahead of what our original initial goals were. And it's definitely ahead of what people thought we would be able to do, especially when you consider when we launched this exploratory committee, most people had never heard of me."

O'Rourke had 218,000 contributions at an average of $43 per donation. His campaign said the majority of the donors had not given to the 2018 Texas Senate campaign, something it points to as a sign of growing grassroots support.

"In just 18 days, people in every state and from every walk of life have organized in homes, contributed a few bucks online and united together to show that the power of people is far greater than the PACs, corporations and special interest that have captured, corrupted and corroded our democracy for far too long," O'Rourke said in a statement.

On Wednesday, candidate Andrew Yang announced that he had raised $1.7 million from more than 80,000 donors, beyond the 65,000-donor threshold the DNC has set to qualify for primary debates. Yang is a lesser-known entrepreneur whose campaign is focused on the issue of displacement of labor by technology and a proposed fix of universal basic income, a $1,000 per month payment to all U.S. citizens over age 18.

Copyright 2023 NPR. To see more, visit https://www.npr.org.