Thomson Reuters launches proprietary AI model for legal work

Global content powerhouse Thomson Reuters Corp. today launched Thomson, its first proprietary large language model, combining the company’s trove of legal knowledge with LLMs from outside providers to provide legal advice.

The company said Thomson will first be deployed in Tabular Analysis, a high-volume document review capability in its CoCounsel Legal AI assistant. CoCounsel will remain a multimodel product, using Thomson for work where the company’s domain-specific model has an advantage and third-party frontier models for other tasks. Thomson will be the default model for Tabular Analysis, although administrators will be able to select other models.

Thomson Reuters spent about $40 million over two years on people and computing for the project, but said economies reduced the cost of the final training run to about $450,000. Instead of building a foundation model from scratch, the company began with an open-weight model and added its proprietary content, training methods and professional expertise. It said the approach reduced both training and inference costs compared with general-purpose frontier models.

The company isn’t seeking to compete with the largest AI labs across every field, said Joel Hron, global head of artificial intelligence and TR Labs at Thomson Reuters. “Thomson needs to set the frontier of intelligence for legal,” he said. “That’s a different job than what I think a lot of the frontier labs are doing.”