The midterm elections were the most expensive ever held in the U.S., and more of the money is “dark” than ever before, making it impossible to get a full picture of who is spending gargantuan sums to influence races that could provide a critical check on Donald Trump’s second term.
The elections have also shown how money in politics is being reshaped, with an increasingly powerful role for big donors from the tech industry and a growing concentration of spending among a few powerful individuals and corporations.
The impact of the rise of mega-donors such as Tesla co-founder Elon Musk, and the increase in dark money among the very top donors, on this year’s electoral outcome is hard to quantify.
But signs of massive spending were everywhere. Ad industry tracker AdImpact predicted $11.6B in ad spending this cycle, surpassing the $ 11.2B spent in the 2024 presidential election. OpenSecrets, a non-partisan research group tracking money in politics, pegs total midterm spending as on track to reach $11.9B.
The top 40 donors have given more than ever before: $2.4B by mid-October, seven times what the top 40 gave in 2014, adjusted for inflation, according to a new analysis from the non-partisan, pro-campaign finance reform institute the Brennan Center for Justice. But the significant difference since then is that those top donors now give more to Republicans, and by a larger differential. In 2014, the top 40 gave to Democrats two to one, but this year the top 40 gave to Republicans three to one more than to Democrats.
Spending from Super PACs, which can accept unlimited amounts of money to spend in elections, hit the $2bn mark by the end of September, which is 51% higher than the last midterm cycle, adjusted for inflation, according to the Brennan Center analysis.
The New York Times also counted at least $1B spent by dark money groups by the end of August. “Dark money” includes organizations such as 501(c)4 non-profits, which are not required to disclose their donors because they are not supposed to have political activity as their primary purpose. (Those rules are often flouted in spirit, if not in practice.) This dark money spending is increasingly widespread in even lower-profile races across the country, and during primary contests. The Brennan Center’s recent number crunching estimated that dark money groups account for an unprecedented 29% share of the top 40 donors and that $699M is largely untraceable.
The landmark 2010 Supreme Court ruling Citizens United changed American campaign finance forever by allowing corporations and labor unions to spend unlimited sums on political expenditures. The cost of the 2010 midterms was only $3.6bn according to OpenSecrets. But rules against Super PACs working closely with campaigns and candidates meant to counter the risk of corruption inherent in unlimited independent election spending are continually flouted and rarely enforced. Trump has repeatedly referred to the Super PAC MAGA Inc. as under his personal control and subject to his decision-making, which violates campaign finance law.
Democrats are about to take control of the House and the Senate, even as Republicans heavily outspent them, with polls showing minimal results from deluges of attack ads in competitive races. Exact figures for the disparity are hard to pin down and keep changing. For example, on Friday, with only days until the election, the former New York City mayor Michael Bloomberg dropped another $36M for Democratic candidates on top of the $80M he already committed. But best estimates showed a steep Republican advantage in Senate race spending, and a narrower one in House races.
The surge in spending was a warning sign for elections ahead, Brennan’s Ian Vandewalker said: “We’ve long had a system of limits and disclosures, but that’s increasingly going away.” Vandewalker points to trends like new, very wealthy industries like AI and cryptocurrency that have burst onto the scene, donating heavily to both parties, “clearly hoping for light or no regulation from the government, which is only going to increase,” and mega-donors like Musk whose major spending “looks like a business investment.”
Bought By Billionaires
Elon Musk’s ideological and personal business interests are well-documented, but other top mega-donors fly below the radar. George Soros is one of the few top-40 individual donors who give primarily to Democrats. Billionaires such as Wall Street’s Jeffrey Yass and the Uihlein family (owners of shipping giant Uline) are longtime Republican mega-givers, focused on school choice and traditional ultraconservative causes, respectively. Combined, the two families gave at least $260m in the 2026 cycle.
Other mega-donors include AI tycoons Marc Andreessen and Ben Horowitz, whose giving focuses on deregulation, advancing the crypto industry, and electing pro-AI candidates. The Israeli American businesswoman Miriam Adelson gave $67M this cycle and is known for advocating for far-right pro-Israel policies from the U.S. government and exerting significant influence on Trump’s U.S.-Israel policies.
Musk has given $483M so far in the midterms, double what Soros gave to Democrats in 2022. The richest person in the world has focused on helping Republicans keep a Senate majority, particularly in a close Texas race. Musk’s business empire and personal fortunes have benefited from his close relationship with Republican candidate Ken Paxton.
New Rules, New Industries
A June Supreme Court decision allowing political parties to spend more in coordination with the candidates they support has helped the GOP pour big money from wealthy donors into small but crucial races, where Democrats previously benefited from raising more directly from smaller donors. Before the ruling, national party committees could only spend from $130,600 to $4,071,800 in coordination with an individual Senate candidate, and from $65,300 to $130,600 in coordination with an individual House candidate. But the court scrapped those limits. The shift means Republican committees have raised more than $48M, dwarfing the $4M additional Democrats added, furthering the influence of big pocketbooks in smaller races that used to benefit from more grassroots local giving.
The past decade has also seen a major shift in the industries that influence elections with major spending. Labor, favoring Democrats, used to account for 14% of the top 40 midterm donors – now, it doesn’t even rank in the top 40, according to Brennan. Traditional finance interest giving has also declined in influence – from almost half of the top 40 donors in 2014 to only 15% this year.
New industries like crypto and artificial intelligence, and the mega-donors associated with them, are crowding out those traditional industries as the scale of big money grows. Even the real estate industry, a longtime steady bipartisan giver, has seen its contributions relatively dwarfed by this new money.
The share of top donors giving to both parties has vastly increased this year, by more than 100 times the levels seen in 2022 and 2018. Strikingly, that means that in this election cycle, the bipartisan big spenders – largely cryptocurrency, online gambling, AI, and pro-Israel interests – gave almost as much to both parties as the top donors giving to only Democrats.
All this cash has resulted in record advertising spending, but with unclear results. Some polling shows very little movement in Senate races in Alaska, Georgia, Maine, Michigan, North Carolina, Ohio, and Texas before and after a GOP ad blitz this fall.
And all of this money doesn’t even account for growing informal influence campaigns – campaign or PAC payments to online social media political influencers are rarely tracked or disclosed. Campaigns can pay through middlemen companies, and the influencers are not required by law to tell their audiences if they are being paid to support a candidate.
Although it’s unknown how exactly the exorbitant spending affected 2026 votes, the bigger shifts cannot be ignored, says Vanderwalker – and serve as a warning for the 2028 election. It’s easier than ever for politicians to rely on one single mega-rich donor, he said: “In a democracy, it’s supposed to be one person, one vote, and the more one person can influence, the less egalitarian our system becomes.”
