Billionaire Profile
Thomas Siebel
Global Rank
#989

Image: Public domain | via Wikimedia Commons

Thomas Siebel

CEO, C3 AI
US
Real-Time Net Worth
$4.1B
As of December 2025
Age
73
Source
Business software
Industry
technology
Citizenship
US

Biography

Thomas Siebel is an American businessman and technologist known for founding Siebel Systems and C3 AI. With a current net worth of $4.1 billion, Siebel's wealth is derived from the business software industry. His career includes executive positions at Oracle Corporation, founding Siebel Systems, and establishing C3 AI, an enterprise AI software company. Siebel is also recognized for his philanthropic contributions, including significant donations to the University of Illinois Urbana-Champaign. He currently serves as the chairman of First Virtual Group.

Wealth Over Time

In-Depth Profile

Early Life and Education

Thomas M. Siebel was born in Chicago, Illinois, on November 20, 1952. He was one of seven children. Siebel attended the University of Illinois Urbana-Champaign, where he earned a Bachelor of Arts in History, a Master of Business Administration, and a Master of Science in Computer Science.

Rise to Success

Siebel's career began at Oracle Corporation, where he held several management positions from 1984 to 1990. In 1993, he founded Siebel Systems, a customer relationship management (CRM) software company. Siebel Systems quickly became a leader in application software. Oracle acquired Siebel Systems in January 2006. In 2009, Siebel founded C3 AI, an enterprise AI software platform and applications company. C3 AI went public in 2020.

Key Business Strategies

Siebel's success is attributed to his deep understanding of information technology. He is the chairman of First Virtual Group, a diversified holding company. He is also the founder of the Montana Meth Project and the Siebel Scholars Foundation. In 2019, Siebel initiated a program at C3 AI that covers the cost for employees to complete the University of Illinois's online Master of Computer Science (MCS) degree through Coursera.

Philanthropy

Siebel is actively involved in philanthropy through the Siebel Foundation. His contributions include donating to the University of Illinois at Urbana-Champaign for the construction of the Siebel Center for Computer Science, and to establish endowed professorships.

Career Milestones

1984

Executive at Oracle Corporation

Held several management positions.

1990

CEO of Gain Technology

Served as CEO of Gain Technology.

1993

Founder and CEO of Siebel Systems

Founded and led Siebel Systems, a CRM software company.

2009

Founder and CEO of C3 AI

Founded C3 AI, an enterprise AI software company.

Philanthropy & Social Impact

Education

Siebel Center for Computer Science

$32M

Donated to the University of Illinois at Urbana-Champaign for its construction.

Education

Endowed Professorships

$4M

Established two endowed full professorships at the University of Illinois.

Education

Siebel Scholars program

Undisclosed

Provides support for MIT graduate students.

Controversies & Challenges

2022

Donated to Canada convoy protest

Donated $90,000 to the Canada convoy protest in Ottawa.

2024

Donated to Donald Trump's re-election campaign

Donated $500,000 to Donald Trump's re-election campaign.

2025

Opposition to California's Proposition 50

Donated $1,000,000 toward funding for opposing of California's Proposition 50