Billionaire investor Ken Griffin has committed approximately $40 million to Republican campaigns in the 2026 midterm elections, with the potential for his total contributions to double by November. Sources familiar with Griffin’s donations say his spending is concentrated on Senate races, signaling a targeted effort to help the Republican Party maintain control of both chambers of Congress.
Griffin’s largest single contribution this cycle was a $10 million donation to the Senate Leadership Fund, which supports Senate Majority Leader John Thune and GOP candidates. He also allocated $6.5 million to political action committees backing individual Republican Senate and House candidates: $2.5 million each for Sen. Dan Sullivan in Alaska and Sen. Susan Collins in Maine, and $1.5 million for Rep. Ashley Hinson in Iowa. The Senate races in Alaska and Maine are considered tossups by the nonpartisan Cook Political Report, while Iowa is rated as leaning Republican. President Donald Trump won Iowa by a substantial margin in 2024.
Despite Texas being rated as leaning Republican, Griffin has opted not to contribute to the campaign of Attorney General Ken Paxton, the GOP Senate nominee, due in part to ongoing legal and ethical controversies surrounding Paxton.
Griffin, who founded and leads the investment firm Citadel, has an estimated net worth exceeding $50 billion. He was among the top political donors in the 2024 election cycle, reportedly the fifth-largest contributor nationwide. Alex Latcham, president of the Senate Leadership Fund, noted that Griffin maintains dialogue with Thune about campaign strategies, policy, and the party’s direction. According to Latcham, Griffin takes an unusually detailed interest in race-specific dynamics and typically backs his involvement with significant financial commitments.
In 2024, Griffin did not back Trump during the Republican primary; instead, he provided $5 million to support former South Carolina Governor Nikki Haley’s campaign, which was the last major GOP bid to conclude before Trump secured the nomination. While Griffin has voted for Trump, he described his support as reluctant. After the 2024 election, he contributed $1 million to Trump’s inaugural committee and commended the former president’s border security measures and efforts combating fentanyl trafficking. However, Griffin has also publicly criticized Trump’s tariff policies and challenges to the Federal Reserve’s independence.
Nonpartisan experts suggest that Democrats currently have a stronger likelihood of reclaiming the House rather than the Senate. Griffin’s contributions this cycle amount to roughly 37% of the donations made by Elon Musk, the leading donor. Sources indicate Griffin’s focus on Senate contests reflects his belief that six-year terms provide a more stable platform for influencing the Republican Party’s future, particularly in preparation for the post-Trump era after January 2029.