The campaigns each had roughly $843,000 remaining at the end of the reporting period, according to campaign finance figures. That money could prove especially important in the final weeks, when campaigns typically pay for advertising, mailers and voter outreach.

Wiener has raised $5.3 million overall, more than twice Chan’s $2.2 million. His campaign has also benefited from $3.3 million in outside spending supporting him and another $1.7 million targeting Chan. Groups supporting Chan have spent about $940,000 on her behalf and $260,000 against Wiener.

Chan’s recent fundraising marked a sharp increase: she collected more during the three-month period than in the previous seven months. Her campaign’s gains came as Pelosi, who endorsed Chan before the primary, held fundraisers that brought in hundreds of thousands of dollars. Pelosi family members contributed $8,000 in late September, while at least 18 current or former Pelosi aides gave Chan a combined $12,310 during the quarter.

Wiener’s campaign has criticized Chan’s fundraising ties to Washington. Spokesperson Joe Arellano said she had received at least $15,250 from 17 donors with federal lobbying records. Chan’s campaign said it would return $3,500 from a pharmaceutical lobbyist. Arellano argued the contributions undercut Chan’s progressive image.

Chan’s campaign, in turn, has attacked Wiener’s ties to technology and wealthy donors. His contributors include crypto executive Chris Larsen, former venture capitalist Jeremy Liew and Twilio co-founder John Wolthuis. Chan spokesperson Ian Krager said Wiener’s positions could shift when donors are involved. Wiener returned a $3,500 contribution from Palantir executive Akash Jain in September, his campaign said, because of the company’s work with Immigration and Customs Enforcement.

Outside spending has largely favored Wiener. The Abundant Future PAC has spent $2.2 million supporting him, including money from Public First Action, a pro-AI-regulation group backed by Anthropic. The company contributed $3 million to support Wiener this quarter. Families for an Affordable San Francisco, which is largely union-funded, has spent $1.6 million for him, as has GrowUSA, the federal political committee of the moderate group GrowSF. Equality California Votes spent an additional $167,000 supporting Wiener.

The spending by Families for an Affordable San Francisco has also drawn scrutiny. A report published Thursday alleged that the group and Wiener’s campaign shared costs for staff, a pollster and an office, potentially testing restrictions on coordination between candidates and super PACs. The group has classified the expenses as canvassing-related; a 2024 Federal Election Commission memo allows super PACs to subsidize certain canvassing costs. The allegation does not establish that campaign finance rules were violated.

Chan’s outside support has come mainly from labor groups, including unions representing hotel workers and teachers. SF for All has spent $575,000 supporting Chan and opposing Wiener since the primary. SF Solidarity, funded by former congressional candidate Saikat Chakrabarti, spent $425,000 on canvassing aimed at winning over Chakrabarti’s primary voters for Chan. Rising Tide Collective spent $100,000 opposing Wiener in September and has not disclosed its funding source.

More spending could follow. Recent filings showed GrowUSA had $1.3 million remaining at the end of September, while Abundant Future had $2.1 million available. SF for All reported $802,000 in its account at the end of August.

Chan is seeking to narrow what her campaign describes as a polling gap by portraying Wiener as aligned with corporate and technology interests. Wiener’s ads emphasize his legislative record and accuse Chan of blocking housing and other legislation. Their competing appeals—and the much larger sums flowing through outside committees—are likely to shape the race’s closing weeks.