Online Ad Spending in the 2024 Election Topped $1.35 Billion

Online political advertising on the two largest digital ad platforms surged in the days leading up to the election, according to a new analysis by the Brennan Center, OpenSecrets, and the Wesleyan Media Project. This analysis builds on our findings this summer using the same publicly reported data from Google and Meta (owner of Facebook and Instagram) and the same transparent methodology.

Our updated findings show that total online political advertising topped $1.35 billion on those two services this election cycle — more than double the amount we measured through the end of August. In other words, advertisers spent more from September 1 through Election Day than they did in the prior 20 months combined. This spike in spending before the election appears to have been driven in large part by fundraising appeals from candidates, as well as an uptick in spending by national groups seeking to influence state ballot measure results.

Key findings

• Online political advertisers spent $1.35 billion to buy ads on Google and Meta this election cycle, with more than half coming in the final two months before the election.
• Spending related to state ballot measures had the largest growth over the last two months, jumping to nearly six times the summer total. Funded largely by out of state donors, spending on the top ballot measure campaigns eclipsed many Senate races, and overall ballot measure spending ($61 million) rivaled the amount spent across all House races ($64 million).
• Some of the largest spenders were groups focused primarily on fundraising appeals, such as the Harris Victory Fund. This reflects the reality that running a grassroots-funded campaign is expensive and requires a broader base of support than a super PAC funded by a few megadonors.

Spending on online political ads on Google and Meta accelerated in the weeks before the election, pushing the overall total to $1.35 billion spent since January 1, 2023. Through August 31, the total spent on such ads was less than half that — $619 million.

The bulk of the increase (40 percent) came from candidates and joint fundraising committees. About a quarter (26 percent) came from super PACs. The next largest chunk (7 percent) targeted ballot measures. Because the candidates and affiliated committees that drove the increase in spending are required by federal law to disclose their donors, the overall transparency in our sample increased compared to our summer analysis, with 63 percent coming from fully disclosing sources (up from 55 percent).

Democrats and their allies continued to dominate online ad spending throughout September and October, outspending their Republican counterparts by nearly three times, just slightly down from the ratio we measured through August.

Consistent with our summer findings, September and October spending concentrated heavily on the presidential race.

Ballot measures were a big target for online ads, with more than $61 million spent to influence the outcomes of campaigns in states across the country. This total is six times the $10 million we measured in our summer analysis. No other category came close to that rate of increase.

Across the entire election cycle, ballot measure spending outpaced the amount spent on governor and down ballot races combined ($45 million) and nearly matched the amount spent on all House races (nearly $64 million). Ballot measure campaigns took up 5 of the top 20 spots in terms of total advertising dollars spent, and 10 spots in the top 30, outspending many Senate campaigns and almost all individual House races.

Notably, funding for ballot measure-related online advertising appears to have come overwhelmingly from national donors rather than in-state residents.

For example, Florida’s Amendment 4, which would have enshrined abortion rights in the state constitution, drew about $9 million in online spending, the most of any ballot measure in our sample. The vast majority of that spending came from Floridians Protecting Freedom, whose largest funders were left-leaning national groups, such as the Fairness Project, Sixteen Thirty Fund, Planned Parenthood, and ACLU, as well as liberal donors and philanthropic foundations like Marsha Zlatin Laufer and the Oklahoma-based Charles and Lynn Schusterman Family Foundation.

Online spending on an abortion rights measure in Ohio in 2023 similarly came from groups bankrolled by out-of-state money. The amendment drew almost $4 million in online ads, split roughly equally between groups supporting and opposing the measure. Ohioans for Reproductive Rights, which was funded by many of the same national donors that supported Florida’s Amendment 4 this year, spent nearly $2 million in support. Opposition came from Protect Women Ohio, which spent about $1.75 million on online ads opposing the amendment, with the vast majority of its funding coming from the conservative advocacy groups like the Concord Fund and Susan B. Anthony Pro-Life America.

Other ballot measures that cracked the top 30 in terms of overall online ad spending —such as California’s Prop 35 (Medicaid funding) and Prop 33 (rent control), Missouri’s Amendment 3 (abortion rights), Ohio’s Issue 1 (redistricting reform), and Nevada’s Question 3 (ranked-choice voting) — also were supported by groups that were heavily reliant on money from national groups.

The biggest online political spender across the election cycle by far was the Harris Victory Fund, a joint fundraising committee that primarily put out fundraising ads. Overall, the Harris Victory Fund spent $179 million on online ads, while the second largest spender —the Harris campaign itself — bought $146 million worth of ads focused on voter persuasion and get-out-the-vote efforts. Harris inherited these committees from President Biden when she took over the top of the Democratic ticket, so not all that spending benefitted her. But it underscores the magnitude of the resources the Harris campaign invested in attempting to generate grassroots support.

By contrast, the Trump campaign spent far less on Google and Meta. Buoyed by massive outside spending from super PACs funded by a handful of billionaire megadonors, the Trump campaign spent just $41 million across the two digital platforms we surveyed (which includes voter persuasion and get-out-the-vote appeals), which was slightly less than the $48 million that Trump’s joint fundraising committees spent.

The Harris campaign’s concentration of spending on fundraising appeals and the stark disparity compared to Trump reflects the fact that fundraising is itself a very costly endeavor.

As with our summer analysis, analysis of online political spending is limited by the lack of federal regulation governing what information platforms make publicly available. The absence of uniform rules means platforms collect and disclose political ad data at their discretion, using different definitions of what constitutes a political ad that can change over time. Some rising categories of spending are left out altogether, such as paid promotion by influencers. As a result, comprehensive analysis is difficult because data is not always available or reliable.

Moreover, we do not know why some campaigns appeared to move away from traditional paid online advertising this cycle. The Trump campaign in particular appears to have relied much less on online ads compared to prior elections, at least on the two major platforms we analyzed. This decrease could be related to Trump seemingly outsourcing much of his campaign to super PACs. Or it could reflect a shift in advertising dollars to entirely new means of engaging with supporters, such as spending on paid influencers, which, as noted, is not captured in our data. Given current limitations in the availability and transparency of online political spending data, we are not able to answer this question.

This analysis relies on political advertising data self-reported by Google and Meta between January 1, 2023, and November 9, 2024, which we downloaded from Google’s weekly Transparency Reports and Meta’s daily Meta Ad Library Reports, and the same methodology as our summer analysis.

Ian Vandewalker and Eric Petry
Brennan Center for Justice

Brendan Glavin
OpenSecrets

Erika Franklin Fowler, Michael Franz, Pavel Oleinikov, Breeze Floyd, and Travis Ridout
Wesleyan Media Project

We are grateful to Josh Bell, Erin Geiger Smith, Grady Yuthok Short, Roberto Cordova, Yujin Kim, Meiqing Zhang, Adriana Begolli, Katherine (Katie) LoCascio, Odin Marin, Emmett Perry, and Nathan Weisbrod for their contributions to this report.