U.S. Sen. Claire McCaskill of Missouri raised more than $4.3 million in the past three months, her campaign announced Wednesday.
McCaskill, who is seeking her third Senate term, has more than $12.2 million in the bank. She's widely considered one of the most vulnerable Senate Democrats running for re-election in November's midterm elections.
McCaskill's possible Republican opponents have raised dramatically less.
The primary election that will determine which Republican gets to face off with McCaskill in November is scheduled for Aug. 7.
Missouri Attorney General Josh Hawley, the GOP's top recruit to challenge McCaskill, raised $1.87 million since the end of March, his campaign said. He has a little more than $3 million in the bank.
Austin Petersen, a libertarian running as a Republican, raised $130,000 in the second quarter, bringing his fundraising total to more than half a million, with contributions that average $41, according to his campaign. Petersen now has $37,000 in the bank.
Two other Republicans — Tony Monetti and Courtland Sykes — did not respond to requests for their latest fundraising totals.
Independent candidate Craig O'Dear raised more than $122,000 over the past three months and has $131,691 on hand, his campaign said Wednesday. O'Dear has raised about $440,000 total so far, a total that includes $140,020 he contributed to his campaign himself.
McCaskill's campaign said 85 percent of the contributions she received in the second quarter were less than $100.
More than 146,000 total donors have contributed to her re-election bid since January 2017, with an average donation of $67, the campaign said.
President Donald Trump carried Missouri by nearly 19 percentage points in 2016.