NetWorth
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Duff
Thomas Duff
Rank #939
UNITED STATES•Diversified•Tires, diversified

Thomas Duff

Net Worth
$4.455B
0% (24h)
Thomas Duff, born December 31, 1956, is an American billionaire businessman and philanthropist. With a net worth of $4.5 billion as of March 2026, Duff is known for co-owning Southern Tire Mart, the largest truck tire dealer and retread manufacturer in the United States, and Duff Capital Investors. His career began in the family business, and he later co-founded Duff Capital Investors with his brother James. Duff is actively involved in philanthropy, donating to various universities and supporting the state's economic growth. He is divorced with two children and resides in Hattiesburg, Mississippi.

How to read Thomas Duff's profile

Public net-worth figures are estimates. They combine observable inputs—typically listed equity, disclosed transactions, and market prices—with editorial judgment where filings are incomplete (for example, private holdings, debt, or cross-holdings). For Thomas Duff, we anchor the narrative to Tires and Tires, diversified, then update the headline number as markets move. The chart on this page is meant to show trajectory, not a certified balance sheet.

When you see $4.455B alongside global rank #939, interpret it as our best synthesis of widely cited ownership and price signals—not a claim about cash on hand. Estimates can diverge from other publishers because of different treatment of options, trusts, charitable vehicles, or illiquid assets. We document the general approach in methodology and welcome corrections via corrections.

Country (UNITED STATES) and career milestones on this page are curated for reader context; they should be verified against primary sources when used for research. Editorial metadata for this profile is refreshed on a rolling basis, with deeper audits at least annually (last noted cycle: 2026).

Looking for depth? When available, the dossier and timeline sections below add long-form context beyond the headline number—prioritize those modules when evaluating claims about strategy, controversies, or philanthropic commitments.

The Full Dossier

Early Life

Thomas Milton Duff was born on December 31, 1956, in Columbia, Mississippi. His parents were Ernest Duff, a lawyer and businessman, and Bobbie Baggett Duff. He graduated from Columbia High School in 1974 and earned a bachelor's degree in business administration from the University of Southern Mississippi in 1979.

Rise to Success

Duff's career began in the tire industry. His father, Ernest Duff, founded Southern Tire Mart in 1973. Thomas and his brother James took over the struggling company in 1983. They later sold the company but bought it back in 2003 and rebranded it. By 2025, Southern Tire Mart's revenues exceeded $4 billion, making it the largest truck tire dealer and retread manufacturer in the nation. The brothers co-founded Duff Capital Investors, a holding company with revenues of $6 billion.

Key Business Strategies

The Duffs focused on hard work and perseverance. They also acquired and turned around failing companies. They streamlined processes, and they expanded by partnering with Pilot Flying J to open locations at their truck stops.

Philanthropy

Thomas Duff is known for significant philanthropic contributions. He and his brother have donated an estimated $50 million to universities in Mississippi, including the University of Southern Mississippi, the University of Mississippi, and Mississippi State University. They made a $26 million gift to the University of Mississippi for a STEM facility.

Career Timeline

2007

Cofounded Duff Capital Investors

Co-founded Duff Capital Investors with his brother James.

2003

Reacquired Southern Tire Mart

Bought back Southern Tire Mart and rebranded it.

1983

Took over Southern Tire Mart

Took over the family business, Southern Tire Mart, with his brother James.

1979

Graduated

Earned a bachelor's degree in business administration from the University of Southern Mississippi.

Philanthropic Impact

Education$30M

University of Southern Mississippi

Pledged collective gifts for scholarships.

Education$26M

University of Mississippi

Donated for the construction of a STEM facility.

Key Business Ventures & Holdings

CompanyStakeValue
Duff Capital Investors——
Southern Tire Mart——

Net Worth History

In-Depth Analysis

Early Life

Thomas Milton Duff was born on December 31, 1956, in Columbia, Mississippi. His parents were Ernest Duff, a lawyer and businessman, and Bobbie Baggett Duff. He graduated from Columbia High School in 1974 and earned a bachelor's degree in business administration from the University of Southern Mississippi in 1979.

Rise to Success

Duff's career began in the tire industry. His father, Ernest Duff, founded Southern Tire Mart in 1973. Thomas and his brother James took over the struggling company in 1983. They later sold the company but bought it back in 2003 and rebranded it. By 2025, Southern Tire Mart's revenues exceeded $4 billion, making it the largest truck tire dealer and retread manufacturer in the nation. The brothers co-founded Duff Capital Investors, a holding company with revenues of $6 billion.

Key Business Strategies

The Duffs focused on hard work and perseverance. They also acquired and turned around failing companies. They streamlined processes, and they expanded by partnering with Pilot Flying J to open locations at their truck stops.

Philanthropy

Thomas Duff is known for significant philanthropic contributions. He and his brother have donated an estimated $50 million to universities in Mississippi, including the University of Southern Mississippi, the University of Mississippi, and Mississippi State University. They made a $26 million gift to the University of Mississippi for a STEM facility.

Data Sources & Methodology

Figures for Thomas Duff are synthesized from the sources below and cross-checked against our net worth methodology. Estimates may lag market moves; see corrections to report discrepancies.

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