$117 MILLION HIT: Study Says Spam Filters Cost Republican Fundraisers 142,000 Potential First-Time Donations
Republican political committees may have lost an estimated $117 million in potential donations after fundraising emails containing WinRed links were disproportionately routed to spam by Gmail, Microsoft Outlook and Yahoo during two periods in 2025, according to a newly published academic study, the NY Post reports.
The research, conducted by University of Iowa finance professor Cameron Ellis and University of Alabama professor Lars Powell, examined Federal Election Commission contribution records alongside email inbox-placement data and paired-email tests. The researchers concluded that approximately 142,126 expected first-time WinRed donations disappeared during periods when Republican fundraising messages experienced unusually severe filtering.
The study itself does not conclude that political bias caused the filtering. Rather, Ellis and Powell say their data demonstrate that specific link-based filtering decisions by major email providers coincided with a dramatic and measurable decline in Republican fundraising while comparable ActBlue-linked messages did not experience the same decline.
One of the episodes began June 30, 2025, when Republican consulting firm Targeted Victory alerted Google that messages containing links to WinRed, the GOP’s principal online fundraising platform, were being diverted to spam. That period continued until September 15, when Google stopped relying on SURBL, an outside service whose blocklist had been identifying WinRed-linked messages as potentially problematic.
During that period, according to the researchers, first-time WinRed donations fell approximately 75% relative to expected levels as messages were filtered by Gmail, Outlook and Yahoo.
A separate episode occurred between February and April 2025 and involved Microsoft Outlook. During that period, first-time WinRed donations dropped 83% compared with normal levels as Republican fundraising emails experienced sharply reduced inbox placement.
Together, the researchers calculated, the two filtering episodes resulted in approximately 142,126 missing first-time donations.
The researchers did not simply multiply the number of missing donations by an average initial contribution. Their $117 million estimate incorporates the projected value of newly acquired donors over time. That distinction is important: the $117 million is an economic estimate of donations researchers believe Republicans would have received from those missing donors, rather than $117 million in individual transactions that were directly blocked by spam filters.
The scale of the estimated loss is particularly striking when compared with overall Republican fundraising. The Republican National Committee, National Republican Congressional Committee and National Republican Senatorial Committee together reported approximately $377 million in fundraising during 2025.
“It’s a pretty big number,” Powell said in an interview with The Post. “You can really think of that as an in-kind gift to ActBlue recipients.”
The researchers were careful, however, not to conclude that Gmail, Outlook or Yahoo deliberately discriminated against Republicans for political reasons.
Instead, the paper concluded that “a narrow, link-level placement decision by a small number of mailbox providers produced a measurable and economically meaningful drop in political fundraising, and that the mechanism was observable only because private paired-test evidence leaked into public reporting.”
The researchers said a central problem is the lack of transparency surrounding the algorithms used by major email providers to decide which messages reach inboxes and which are routed into spam.
In explaining the difficulty of determining why particular filtering decisions were made, Powell said “we can’t read their minds.”
Google strongly disputed the study’s conclusions and methodology.
A Google spokesperson said the research “relies on deeply flawed methodology that fundamentally misunderstands how Gmail works.”
“Our spam protections apply equally to everyone, regardless of political affiliation and we encourage bulk senders to follow best practices to reach inboxes,” the spokesperson added. “Ultimately, people are in full control of their inboxes, with the power to mark messages as spam, block senders, or unsubscribe at any time.”
Google also challenged the $117 million estimate, arguing that the figure represents a theoretical calculation of the value of donors who researchers believe were lost rather than an accounting of specific contributions that unquestionably would have occurred.
Microsoft declined to comment on the findings, while Yahoo did not respond to a request for comment.
To conduct the analysis, Ellis and Powell examined itemized Federal Election Commission contribution records and separated first-time donors from repeat donors using WinRed and ActBlue.
They then compared donation patterns with inbox-placement data covering periods in which Republican messages were being filtered. This allowed them to estimate how many new contributions would normally have been expected during those periods.
“Inbox placement data and paired email tests showed when the filtering happened and supported that WinRed links were the trigger,” Powell said.
The findings add new data to a controversy that has simmered for years over whether email providers treat political messages from Republicans and Democrats differently.
Republicans have repeatedly accused Google in particular of disproportionately filtering conservative political emails. Google has consistently denied intentionally favoring one political party and has said its automated systems evaluate messages according to factors designed to protect users from spam and unwanted email.
Previous legal and regulatory challenges did not establish unlawful political discrimination by Google. In 2023, the Federal Election Commission dismissed an RNC complaint involving Gmail, finding “no reason to believe” Google had violated federal election law. A federal judge also dismissed a separate Republican National Committee lawsuit against Google in 2024.
The 2025 controversy took another turn when Targeted Victory conducted paired-email testing. According to the Republican consulting firm, messages containing WinRed links were flagged while otherwise identical messages containing ActBlue links were successfully delivered.
Targeted Victory said some Republican fundraising messages were not merely sent to spam but were marked by Gmail as “dangerous.”
The complaints attracted the attention of Federal Trade Commission Chairman Andrew Ferguson, who wrote Google CEO Sundar Pichai warning that politically discriminatory email filtering could potentially raise consumer-protection concerns.
Google subsequently stopped using SURBL in Gmail’s filtering system on September 15, 2025. Ellis and Powell reported that Republican email inbox placement “normalized” after that change.
Republican officials say the new academic findings bolster their longstanding contention that the filtering had significant real-world consequences.
“Google’s biased algorithms sidelined Republican fundraising emails for years while boosting Democrats’ donor outreach,” Bernadette Breslin, press secretary for the National Republican Senatorial Committee, told The Post.
“The NRSC has helped lead the investigation into Google’s suppression of mail to conservative subscribers, and this long-overdue update is a chance to level the playing field for online fundraising,” Breslin added.
A Republican adviser familiar with the dispute similarly described the findings as a “massive proof point in what we already knew to be true.”
“Smoking gun that conservatives are being systematically disenfranchised,” the adviser added.
Meanwhile, Gmail has changed the way qualifying political email can be handled. Google launched a Verified Sender Program for eligible American political committees, including candidates, political parties and PACs.
Under the program, participating organizations must verify their identities and sending domains and satisfy Gmail’s technical and security requirements. They must also maintain compliance with the program’s policies.
The program is intended to improve deliverability for authenticated political senders while leaving individual Gmail users with the ability to mark messages as spam, block senders or unsubscribe.
Powell said he had not discussed his study with Google and could not say whether the new policy resulted from the controversy. He suggested, however, that business considerations could ultimately influence how Google responds to complaints from political email senders.
“They make money by having people send more emails. If people start changing, that’s bad for their business model,” Powell said. “I think that’s when we find out whether they’re more blue or green.”
The researchers’ central finding remains narrower than the partisan accusations surrounding it: during two identifiable periods when WinRed-linked messages suffered sharp drops in inbox placement, Republican first-time donations fell dramatically, while comparable Democratic fundraising did not show the same pattern.
Whether those filtering decisions resulted from political bias, technical spam-detection rules or other factors remains disputed. What Ellis and Powell say their data establish is the financial consequence: an estimated 142,126 lost first-time Republican donors with a projected value of approximately $117 million.
