Hogan’s fundraising network raised $6.6 million between April 1 and June 30, outpacing Alsobrooks’s campaign by nearly $1 million, according to Federal Election Commission filings by the campaigns on Monday. A former governor who remained popular among Maryland voters after leaving office in 2023, Hogan had $3.3 million in cash on hand across his primary campaign committee and its joint fundraising partners.

“Our campaign is incredibly humbled by the support we’ve received across the state,” Hogan for Maryland spokeswoman Blake Kernen said in a statement. “Marylanders are fed up with politics as usual and are hungry for strong, independent leadership in Washington to put people over politics.”

The Alsobrooks campaign raised $5.7 million in total contributions across her fundraising network during the second quarter, with $3.7 million in cash on hand at June 30. The campaign said it received donations from every county in the state, and increased its pool of donors more than fivefold over the previous quarter.

“We continue to build upon our grassroots movement because voters know I will fight for them and their families, because we all want the same things; for our freedoms to be protected, to feel safe in our communities, to have access to quality education, and a job that treats us with dignity and respect,” said Alsobrooks, executive of Maryland’s second-largest county, Prince George’s, in a statement.

The high-stakes matchup in deeply Democratic Maryland is one of a few expected to determine the balance of power in the Senate.

Hogan left the governor’s office with record-high job approval ratings among both Democrats and Republicans, and a national brand as a Donald Trump critic. He said he did not plan to travel to the Republican National Convention, which he hasn’t attended since before Trump’s 2016 nomination.

Alsobrooks has made a case to voters that regardless of what Hogan says, electing him to the Senate, where Democrats now hold a slim majority, could empower a Republican majority aligned with Trump’s agenda.

Hogan’s own fundraising haul could be eclipsed by a super PAC created days after the February launch of his Senate bid. The super PAC, called Maryland’s Future, has stockpiled more than $15 million. Super PACs are allowed to raise and spend unlimited amounts of money on political activity, so long as they don’t coordinate with candidates they benefit.

Maryland’s Future received an initial $10-million infusion from Republican megadonor Ken Griffin, who backed Nikki Haley in this year’s Republican presidential primary and remained resistant afterward to giving money to Trump, telling others he did not have plans to fall in line with the former president, according to people who spoke with him.

Between April and June, Maryland’s Future received additional big-dollar injections, including: $2 million from Stephen A. Schwarzman, chairman, CEO and co-founder of the investment firm Blackstone; $1 million from Craig J. Duchossois, a Chicago-based investor; and $150,000 from Harlan R. Crow, the Texas billionaire recently in the news for providing lavish vacations to Supreme Court Justice Clarence Thomas.

Maryland’s Future also received $1 million from Warren A. Stephens, a longtime Republican donor and investment banker who also has given to each of Hogan’s joint fundraising committees and his leadership PAC. Stephens was a major financial backer of efforts to stop Trump from being elected in 2016. Like Griffin, he backed Haley in the primary, but he has since shown support for Trump, with his name appearing among billionaire hosts of a fundraiser planned for the former president in April.

The super PAC lists its address as that of a Staples store in Annapolis. Its treasurer is an Alabama-based accountant, Craig Mareno, who was also listed in documents last year creating a super PAC backing Florida Gov. Ron DeSantis’ presidential bid. Reached by phone Tuesday, Mareno declined to comment. The Washington Post did not immediately get a response to a message sent to an email address listed for Maryland’s Future.

Nearly all of the super PAC’s funders are from out of state. But Michael D. Epstein, president of Willow Asset Management in Rockville, Md., gave $25,000. Last month, he retweeted a post on X by Republicans against Trump, noting the former president is a felon and saying it was embarrassing for him that Hogan rejected his support. Epstein could not be reached for comment.

Several left-leaning political action committees have contributed to Alsobrooks’s campaign, including Sen. Tim Kaine’s (D-Va.) group Common Ground PAC, which gave $10,000 in May after the primary. Emily’s List, a national group that supports Democratic abortion rights advocates women running for office, gave $5,000 to support Alsobrooks in May, and has given the campaign $10,000 total this election cycle.

Alsobrooks on Monday touted an “outpouring of support from people all across this state.” Of the total dollar figure for itemized donations reported by her campaign network, 54 percent came from contributors inside the state, according to a Washington Post analysis of Federal Election Commission data. Of Hogan’s itemized donation total, 41 percent came from inside the state, the analysis showed. (Campaigns are only required to record details for — or “itemize” — donations from individuals who have given at least $200.)

Paul Schwartzman contributed to this report.