Tencent Releases Hy3: Open 295B MoE Model with 21B Active Parameters and 256K Context

Tencent has open-released Hy3, a 295-billion-parameter Mixture-of-Experts model that activates only 21B parameters per forward pass, making inference significantly more tractable than its total size implies. The model supports a 256K token context window, which puts it in direct competition with frontier-tier long-context models. Being fully open, developers can self-host, fine-tune, and deploy Hy3 without API gating or usage restrictions. The MoE architecture means it can run on reasonable multi-GPU setups rather than requiring warehouse-scale compute for inference. This is a meaningful addition to the open-weight ecosystem and worth benchmarking against Mixtral and DeepSeek MoE variants for long-document and agentic tasks.