# Siebel Systems founder Tom Siebel gave $50,000 to San Jose Mayor Matt Mahan’s bid for California governor.

*business · news · 2026-04-17 · New York Post*

## Key points

- Tom Siebel, cousin of Jennifer Siebel Newsom, contributed $50,000 to Matt Mahan's gubernatorial campaign.
- Siebel also donated $10,000 to Steve Hilton, a Republican critic of Gov. Gavin Newsom.
- Previously, Siebel was the third-largest donor against Prop. 50, opposing Gavin Newsom’s redistricting effort.
- Tom Siebel supported Donald Trump in 2024 with a $500,000 donation and hosted a fundraiser.

**Companies:** Oracle, Siebel Systems
**Countries:** United States

[Read the full story on New York Post](https://nypost.com/2026/04/17/us-news/gavin-newsoms-wifes-billionaire-cousin-tom-siebel-funds-matt-mahan-and-steve-hilton/)

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