GiveRate / All records / Forbes 400 (Sept. 2026) / Thomas Siebel
Thomas Siebel
5–10%
Thomas Siebel has given an estimated 5–10% of current net worth ($4.5B), based on Forbes' philanthropy score.
- GiveRate
- 5–10%
- Net worth
- $4.5B
- Stated lifetime giving
- Not stated
- Forbes 400
- #380 · Business software · Woodside, California
- Status
- Source-reported range
- Sources
- Forbes 400 profile · Sept. 2026
The math
Forbes philanthropy score 3 of 5: lifetime giving is 5–10% of current net worth. The range is Forbes' own banding; GiveRate shows it as published.
Profile
- Age
- 73
- Residence
- Woodside, California
- Industry
- Technology
- Source of wealth
- Business software
- Self-made
- Yes
- One-year change
- $4.1B (#362) in Sept. 2025 to $4.5B (#380) in Sept. 2026, a gain of 10%.
What the range means in dollars
Forbes gives Thomas Siebel a philanthropy score of 3 out of 5, meaning lifetime giving equals 5% to 10% of current net worth. On a $4.5B fortune, that implies lifetime giving of roughly between $225M and $450M. 38 of the 400 share this score, 315 score lower and 30 score higher.
For scale: 5% to 10% of a $50,000 household income would be $2,500 to $5,000.
Others in Technology
- Elon Musk: Under 1% · $908B
- Jeff Bezos: 1–5% · $378B
- Larry Page: Under 1% · $278B
- Michael Dell: 1–5% · $263B
- Sergey Brin: 1–5% · $256B
- Mark Zuckerberg: 1–5% · $212B
Others in California
- Larry Page: Under 1% · $278B
- Sergey Brin: 1–5% · $256B
- Mark Zuckerberg: 1–5% · $212B
- Jensen Huang: Under 1% · $199B
- Eric Schmidt: 5–10% · $37.8B
- Henry Samueli: 1–5% · $33.8B
Questions
How much has Thomas Siebel given to charity?
Forbes scores Thomas Siebel 3 of 5 for philanthropy, meaning lifetime giving of 5% to 10% of net worth, roughly between $225M and $450M on a $4.5B fortune.
What is Thomas Siebel's net worth?
Forbes estimates $4.5B as of September 2026, ranking #380 on the Forbes 400.
What is Thomas Siebel's GiveRate?
5–10%. GiveRate is lifetime giving as a share of wealth, built from published Forbes figures. See giverate.org/methods/ for the method.
GiveRate is an estimate built only from the published figures above. Wealth and giving totals are themselves estimates. See methods. Spot an error? Request a correction. See all Forbes 400 (Sept. 2026) · Open in the interactive rankings · Calculate your own GiveRate