Siebel, Th

Technology entrepreneur Thomas Siebel has been a funder of Donald Trump and other Republican campaigns. Most recently, Siebel hosted and contributed to Trump's 2024 re-election efforts.

Political contributions to Trump

• 2024 re-election campaign: Siebel contributed $500,000 directly to Trump's re-election campaign and organized a major fundraiser in Woodside, California, in September 2024.
• Fundraiser tickets: Tickets for the 2024 Woodside event, held at Siebel's home, went for up to $500,000 per couple.
• Inauguration and PACs: Records also show Siebel has contributed to Republican and pro-Trump political action committees (PACs) over the years. For instance, recent reports show he contributed $1 million to a PAC backing California's Proposition 50, a committee that also received major funding from Trump's political allies.

Other political activities

• Freedom Convoy (2022): Siebel provided the largest single donation ($90,000) to the Canadian "Freedom Convoy" trucker protest against COVID-19 vaccine mandates.
• Republican donor: Federal Election Commission records indicate Siebel has donated hundreds of thousands of dollars to Republican candidates and organizations since the early 2000s.

About Thomas Siebel

• Background: A Silicon Valley-based billionaire, Siebel is a veteran of the software industry.
• Siebel Systems: He is best known as the founder and chairman of Siebel Systems, a software company acquired by Oracle in 2006.
• C3.ai: He is currently the CEO of the artificial intelligence software company C3.ai.

As of late September 2025, the primary funders of the "No on Proposition 50" campaign in California are physicist and political donor Charles T. Munger Jr., and software entrepreneur Thomas M. Siebel.

Charles T. Munger Jr.

• Total Contributions: Munger is the largest donor by a wide margin, contributing more than $30 million to defeat Proposition 50.
• Political Context: He is a prominent Republican donor who previously championed California's independent redistricting commission, which Proposition 50 would temporarily override. His funding is driven by his opposition to gerrymandering, regardless of which party initiates it.
• Campaign Vehicle: Munger has funneled his donations through the "Protect Voters First" campaign, which targets moderate and unaffiliated voters.

Thomas M. Siebel

• Total Contributions: Siebel, the founder and chairman of the software company C3.ai, Inc., contributed $1 million to the opposition campaign.
• Political Context: He is part of a separate "No on 50" committee, "Stop Sacramento's Power Grab," which is also backed by other Republican figures, including former Speaker Kevin McCarthy.

Other significant "No on 50" funders

• Congressional Leadership Fund (CLF): This Republican super PAC has contributed $5 million to the campaign opposing Proposition 50.
• Kevin McCarthy for Congress PAC: The former Speaker of the U.S. House contributed $1 million through his political action committe