He moved into the airline business in 1965, when he acquired Britannia Airways, and into oil and gas exploration in 1971, when he participated in a consortium to exploit reserves in the North Sea.

In 1996, the Thomson Corporation acquired West Publishing, a purveyor of legal research and services (including Westlaw).

[10] Reuters began to grow rapidly in the 1980s, widening the range of its business products and expanding its global reporting network for media, financial and economic services.

[18] The European Commission imposed similar divestments: according to the commission's press release, "the parties committed to divest the databases containing the content sets of such financial information products, together with relevant assets, personnel and customer base as appropriate to allow purchasers of the databases and assets to quickly establish themselves as a credible competitive force in the marketplace in competition with the merged entity, re-establishing the pre-merger rivalry in the respective fields.

According to the Financial Times, "the remedy proposed by the competition authorities will affect no more than $25m of the new Thomson Reuters group's $13bn-plus combined revenues.

[21] In November 2009, the European Commission opened formal antitrust proceedings[22] against Thomson Reuters concerning a potential infringement of the EC Treaty's rules on abuse of a dominant market position (Article 82).

[31] Former divisions: Intellectual Property & Science, Financial & Risk, Thomson Healthcare, and Scholarly & Scientific Research.

[34] In 2012, Thomson Reuters sold its Healthcare division to Veritas Capital, who renamed the business Truven Health Analytics.

[36] On June 30, 2022, Francisco Partners announced the completion of acquiring Watson Health and launched a healthcare data company named Merative.

[38] In 2016, Thomson Reuters struck a $3.55 billion deal in which they spun it off as an independent company, and sold it to private-equity firms Onex Corporation and Baring Private Equity Asia.

)[42] In 2009, Thomas Reuters acquired numerous companies, including data mining provider Streamlogics,[43] tick data company Vhayu Technologies,[44] European PR distribution group Hugin Group,[45] Breaking Views, and Deloitte's Abacus corporate taxation software.

[32] This includes: Thomson Reuters has sponsored Canadian golf champion Mike Weir[107] and the Williams Grand Prix Engineering Formula One team.

[109] Thomson Reuters owns and operates the Consolidated Lead Evaluation and Reporting (CLEAR) database,[110][111][112] which scrapes personal and identifying data for use in law enforcement, corporate security, and fraud investigations.

A company representative replied that Thomson Reuters will help the American government and police in active criminal investigations and against threats to national security or public safety.

[121] In 2020, three Reuters investigative journalists, Raphael Satter, Christopher Bing and Jack Stubbs, who were conducting an investigation about a hack-for-hire company based in India, forcefully took a photograph of Kumar, a small scale Indian herbal businessman for an alleged hacker Sumit Gupta of Belltrox.