Key points:
- Thomson Reuters' CoCounsel AI platform has reached one million users across more than 100 countries, sending the company's shares up more than 10% on the news.
- The milestone reflects a broader shift in legal, tax and compliance work — but Thomson Reuters' CTO is frank that adoption alone does not mean the product yet fully meets professional expectations.
- The company says its next phase of development will focus on closing the gap between reliability and genuine utility, with agentic AI workflows set to expand in 2026.
When Thomson Reuters announced that its CoCounsel AI platform had crossed the one million user mark, the market reacted swiftly: shares rose more than 10% in a single trading session. For a company that has spent the better part of two years repositioning itself from a content business into an AI-powered technology company, the number carries weight — though Thomson Reuters' own Chief Technology Officer, Joel Hron, is careful not to oversell it.
"One million is not enough," Hron wrote in a post accompanying the announcement. "We are winning the professional AI market for legal, tax, and compliance — but we are not dominating it. Not yet." That kind of candour is notable in a market where AI announcements tend toward the breathless. CoCounsel, which grew out of Thomson Reuters' $650 million acquisition of legal AI startup Casetext in 2023, is now in use across more than 100 countries and territories, spanning legal, tax and compliance professionals.
The candour extends to the product itself. Hron acknowledged that the company's early emphasis on accuracy and trust — adding verification layers, human review checkpoints and conservative thresholds — produced an AI that users could rely on, but one that could feel more cautious than genuinely helpful. "We optimised for never being wrong," he wrote. "Our users wanted us to also optimise for being genuinely helpful." That tension — between precision and fluency, between reliability and delight — is a structural challenge for every enterprise AI vendor building for regulated industries, and Thomson Reuters is now explicitly naming it as its next priority.
For in-house legal teams and law firm technology leaders, the CoCounsel milestone is worth examining beyond the headline number. Three years after CoCounsel launched as one of the first dedicated legal AI assistants, the product's evolution tracks closely with the broader arc of enterprise legal AI: early adoption driven by curiosity and efficiency gains, followed by harder questions about workflow integration, governance, and measurable ROI.
Thomson Reuters says additional capabilities for CoCounsel Tax and its ONESOURCE+ platform are planned for later in 2026, with agentic AI — systems capable of executing multi-step tasks autonomously — positioned as the next frontier. For legal ops leaders evaluating AI investments this year, the question is no longer whether to adopt, but how to structure adoption so that the tools deliver outcomes that can be measured and defended to the board.
