Billionaire Profile

Global Rank

#1266

Image: Public domain | via Wikimedia Commons

William Chisholm

CEO, STG Partners

Real-Time Net Worth

$3.2B

As of December 2025

Age

Source

Private equity

Industry

finance-investments

Citizenship

Biography

William "Bill" Chisholm, a 56-year-old US citizen, is a prominent figure in the private equity world. His wealth source is private equity, making him a self-made billionaire. Chisholm is the managing partner and chief investment officer of STG Partners, a software-focused private equity firm. His career includes key roles at Bain & Company and PaineWebber. In March 2025, he led an investment group to acquire the Boston Celtics for $6.1 billion. This acquisition solidified his place in the sports world. Chisholm's achievements also include co-founding Symphony Technology Group. He attended Dartmouth College and The Wharton School at the University of Pennsylvania. The Celtics acquisition is expected to significantly increase his net worth, estimated at $3.2 billion as of December 5, 2025. He is married and has three children.

Wealth Over Time

Portfolio Holdings

Boston Celtics

In-Depth Profile

Early Life

William "Bill" Chisholm grew up in Georgetown, Massachusetts. He attended Brooks School, where he played basketball, lacrosse, and soccer. Chisholm graduated from Brooks in 1987. He went on to Dartmouth College, where he played for the soccer team. He graduated in 1991. He later received a Master of Business Administration (MBA) from The Wharton School at the University of Pennsylvania in 1996.

Rise to Success

After Dartmouth, Chisholm worked as an analyst for PaineWebber. From August 1996 to January 2000, he served as a management consultant at Bain & Company. In 2002, Chisholm co-founded Symphony Technology Group (STG) with software billionaire Romesh Wadhwani. Chisholm's strategy was to acquire undervalued or underperforming enterprise software companies and unlock their potential.

Key Business Strategies

STG focuses on operational improvements. This value-creation model proved successful, with the firm investing $1.6 billion over 15 years and returning $10 billion to investors. In 2017, Chisholm took full leadership, rebranding the firm as STG Partners. The firm has over $11 billion in assets. A signature deal was the acquisition of Information Resources, later renamed IRI. In 2025, he led an investment group to acquire the Boston Celtics for a staggering $6.1 billion.

Philanthropy

Chisholm, along with his wife, is involved with Breakthrough T1D, a research and advocacy organization for Type 1 diabetes.

Career Milestones

1991

Graduated Dartmouth College

Received a Bachelor of Arts degree.

1996

Graduated The Wharton School

Received a Master of Business Administration.

2002

Co-founded Symphony Technology Group

Co-founded the private equity firm, which later became STG Partners.

2025

Agreed to purchase Boston Celtics

Led an investment group to acquire the Boston Celtics for $6.1 billion.

Philanthropy & Social Impact

Health Research

Breakthrough T1D

Undisclosed

Chisholm and his wife are involved with this organization.