Thomson is a co-chairman of Woodbridge, the investment firm that controls Thomson Reuters. The Ontario, Canada-based firm owns about 70% of the publicly-traded financial data and services provider, which had revenue of $7.5 billion in 2025. He owns about 14% of Woodbridge's assets and his relatives own the rest.
The majority of Thomson's fortune is derived from Woodbridge, an investment firm that manages the family fortune originated by Canadian media magnate Roy Thomson. After his death in 1976, Thomson's estate was divided between his three children. His son -- and David Thomson's father, Kenneth -- inherited 42%. His two daughters, Audrey and Irma, received 33% and 23%, respectively, according to a person familiar with the family's assets who asked not to be identified because Woodbridge is closely held.
Each heir evenly split their share in Woodbridge among their children, the source said. David and his two siblings, Peter and Taylor, each received 14% of Woodbridge. Each of Audrey's three children, Linda Campbell, Susan Grange and Gaye Farncombe, received 11%. A cousin, Sherry Brydson, the only child of Irma, owns about 23%. David is calculated in this analysis to own 14% of Woodbridge's stake in Thomson Reuters.
Woodbridge owns about 70% of Thomson Reuters, according to proxy and SEDI filings from March 2026. It's pledged about 3 million shares to secure various credit facilities, according to a Nov, 2025 13D filing. Thomson's portion of the pledged shares has been excluded from his net worth valuation.
The value of his cash and closely held investments is based on Woodbridge asset values as disclosed in a 2007 investor presentation and adjusted to reflect dividends, insider transactions, taxes and market performance. David's share also includes proceeds from land sales associated with Osmington, his real estate company.
In 2011, Thomson and hockey executive Mark Chipman purchased the NHL's Winnipeg Jets. Thomson is the sole minority shareholder and is credited with a 40% stake in the club, which is valued based on an October 2025 analysis from valuation consultants Sportico.
Thomson, through spokesman for Thomson Reuters David Girardin, didn't respond to requests for comment.
Canada's richest family was set on its path to wealth in 1931, when Roy Thomson acquired a radio station in Ontario. Two years later he bought the Timmins Press, a newspaper in Ontario. Within five years, Thomson was Canada's leading newspaper owner. After aggressive expansion in the UK, he sold shares in a public offering in 1965, with his son Kenneth taking over in 1976.
Kenneth's eldest son, David K. R. Thomson, took the reins of the family fortune on his father's death in June 2006. Today, most Thomson investments are made through Woodbridge, a family-owned investment company of which brother Peter is chairman.
As chairman of Thomson, David continued to expand the business, announcing a merger with Reuters in 2007. Woodbridge owns 63.4 percent of the combined company, Thomson Reuters, as well as holdings in commodity analyst IHS and Canada telecommunications company BCE. Woodbridge also has billions of dollars in closely held investments.
Outside of Woodbridge, David controls personal investments through closely held Osmington, a real estate company. He sold most of his shopping center interests to the Canada Pension Plan in 2010, and property management arm Redcliff to Calgary's Coril in 2011.
Thomson owns artwork by John Constable and is the sole owner of a minority stake of the Winnipeg Jets hockey franchise.