Thomson Reuters spent about $40 million over two years building "Thomson," its first in-house legal language model, on Alibaba's Qwen. In testing, Thomson only outperforms GPT-5.4 when given access to exclusive company content; with web access alone it trails 0.53 to 0.65. A safety-focused intermediate version, "Snowdon," was developed with Imperial College. Thomson debuts in CoCounsel document review, and a smaller open-weight version will be released under a non-commercial license.
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