Campbell owns 11% of Woodbridge, a closely held investment firm that manages the fortunes of the six surviving grandchildren of Canadian media magnate Roy Thomson. The Ontario-based company owns a 70% stake in Thomson Reuters, a financial data and services provider that reported revenue of $7.5 billion in 2025.
The majority of Campbell's fortune is controlled by 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, Kenneth, inherited 42% and 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%. Campbell is calculated in this analysis to own 11% 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 the same filing. Campbell's portion of the pledged shares has been excluded from her net worth valuation.
Cash & Other Assets is based on Woodbridge asset values as disclosed in a 2007 investor presentation 2007 and adjusted to reflect dividends, insider transactions, taxes and market performance. The family has collected more than $3 billion in dividend income and share sales since then, based on an analysis of company filings and Bloomberg data.
David Girardin, a spokesman for Thomson Reuters, 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 North Bay, Ontario. Two years later he bought the Timmins Press, a newspaper in Ontario. Within five years, Thomson was Canada's leading newspaper owner. After expanding in the UK, he sold shares in a public offering in 1965, with his son Kenneth taking over the business in 1976.
While Kenneth ran the family business, Roy's two daughters also inherited large minority stakes in the company. Audrey, Campbell's mother, was the oldest of the children. She married Elwood Campbell, a high school science teacher, and raised their three children in Port Credit, Ontario, a town on the shores of Lake Ontario.
Campbell, with her sisters, gave $30 million to the Centre for Addiction and Mental Health in Toronto, and with her cousin Sherry Brydson they also endowed a downtown YWCA. In 2004, with her mother and sisters, Campbell directed what was then Canada's largest ever donation to a hospital -- $67.5 million over four years -- to support cancer research.