Thomson Reuters built its own model for $40M to stop renting AI from Anthropic
Thomson Reuters unveiled Thomson, its first proprietary LLM, trained on decades of Westlaw, Practical Law, and Reuters content starting from an open-source foundation. The whole build cost $40 million over two years, with the final training run around $450,000, a rounding error next to frontier-lab budgets. It is already taking document review work off Anthropic's Claude inside CoCounsel Legal, a bet that owning the model beats renting it.