Tencent unveils hy4 preview model, positions itself as leading open-source AI model

On August 28, 2026, Tencent officially launched the Hy4 preview model, featuring 770 billion parameters, 49 billion active parameters, and a 1 million token context length. The model represents a significant advancement in size, context length, and data scale, with improvements in both pre-training and post-training phases. Tencent claims the Hy4 preview model remains in the top tier of open-source models. The model has been developed with high-quality data from internal experts across software engineering, finance, gaming, and security. It excels in tasks such as software development, office analysis, game creation, and scientific research. In benchmark tests, Hy4 preview outperformed GLM-5.3 and Kimi K3, with a score of 2.99/4.00. The model also made progress on the Blaschke–Lebesgue problem, raising the volume lower bound to 0.41104. Tencent emphasized that Hy4 preview is an early version with room for further improvement and ongoing refinement.