Tencent opened its biggest model yet — and on its own chart every rival scores higher

Tencent published the weights of Hy4 preview on 27 August 2026, two weeks after telling investors the model was still in training. At 770B total parameters with 49B active per token, it is the largest flagship the company has released, and it comes under the Apache 2.0 licence — verified in the licence file itself, with no clause reserving commercial use. The technical step is real. The backbone runs 78 layers, all but the first built as mixture-of-experts blocks with 256 routed experts and one shared expert, and a built-in multi-token-prediction layer for speculative decoding pushes the published file to 780B parameters, about 1.6 TB in BF16. The context window is a million tokens. Tencent also shipped an FP8 edition, a finetuning pipeline and its own compression toolkit, so the model is meant to be run by outsiders, not just admired. The comparison chart Tencent chose to publish is the more interesting document. It has twelve panels, and in every one of them the highest score belongs to somebody else — most often Claude Opus 5 or GPT-5.6 Sol. Hy4 preview scores 85.4 on Terminal Bench 2.1 where GLM 5.3 and GPT-5.6 Sol both reach 88.3. On the text-only Humanity's Last Exam it scores 43.4 against 53.2 for Claude Opus 5. On ProgramBench it scores 17.5 against 39.5. Against the other Chinese open-weights models it is mid-pack: ahead of DeepSeek V4 Pro on all three, level with Qwen 3.8 Max on two, behind Kimi K3 on two. What the chart does show, clearly, is distance travelled. On those same three tests Hy3 scored 70.8, 34.4 and 3.0 — the ProgramBench figure went from near-zero to competitive in seven weeks of generational change. Tencent's own summary is unusually plain about the rest: this is an early version, it reasons longer than it needs to, it over-verifies its own answers, and the company would rather ship it and hear what breaks. It made the same choice with Hy3 preview, which shipped in April and reached its official release in July. One detail contradicts the run-up. Press reports through August said Hy4 would be Tencent's first multimodal flagship. The preview takes text in and returns text out.