Hy4 Preview

Hy4 Preview is an open-weight model from Tencent, released August 28, 2026. It ranks #28 of 44 models on the Vals Index with 49.94%. Its best result is #7 of 47 on Public Benefits Bench v1.1.

Release Date: Aug 28, 2026

Developer Tencent Β πŸ‡¨πŸ‡³
Context Window 1M
Max Output Tokens 64k
Token Costs (in/out) $0.83/2.50
Weights Open
Input Modalities

Accuracy

49.94 % Β± 1.15

Cost / Test (Vals Index)

$ 1.439

Latency

60 min 57 s

Vals Index
BenchmarksAccuracyRankings

49.94%

Β±1.15
28/44

47.43%

Β±4.27
12/74

65.36%

Β±5.55
29/44

58.08%

Β±3.14
34/71

55.06%

Β±0.31
19/75

45.19%

Β±3.46
16/74

43.25%

Β±2.13
45/105

83.60%

Β±2.06
43/107

75.00%

Β±4.35
13/47

68.61%

Β±1.21
7/47

2.29%

Β±0.93
22/32

63.71%

Β±3.26
23/66

77.48%

Β±4.04
28/109

69.26%

Β±2.59
12/24

59.33%

Β±4.60
15/41

83.76%

Β±0.41
48/149

0.00%

Β±0.00
30/62

8.08%

Β±1.34
35/44

1.43%

Β±1.43
33/38
Proprietary BenchmarksAcademic BenchmarksIndustry Partners
Vals
Default Provider : Tencent
Temperature: 0.9
Top P: 1
Top K: Default
Max Output Tokens: 64,000

Compared with

Updates

Sep 17, 2026

We evaluated Tencent’s open-weight Hy4 Preview across our benchmark suite.

  • #21 of 58 on the Vals Index (55.40%) at $1.28 per test, the #4 open-weight model behind DeepSeek V4.1 Flash, Kimi K3 and GLM 5.3.

  • Best open-weight model we’ve tested on Code Migration (47.43%, #7 of 61, at $3.41 per test versus $24.91 for GLM 5.3), Public Benefits Bench (68.61%, #4 of 36, behind only three Anthropic models) and SRE Bench (2.29%, #7 of 10).

  • Strong on reasoning and legal work: 75.00% on ProofBench v1.1 (#8 of 32), 59.33% on IOI (#10 of 28), 45.19% on Legal Research Bench (#10 of 61) and 9.17% on Harvey’s Legal Agent Benchmark (#13 of 62). Weaker on Terminal-Bench 2.1 (55.06%, #42 of 66), MedCode (43.25%, #37 of 93) and MedScribe (83.60%, #35 of 95).

  • Cost per test is below the board median on nearly every benchmark, skewing higher on benchmarks that involve files. Latency is medium-high for a model of its size and price (measured at low concurrency): closest to peers on math and science, slowest on routine knowledge work such as MedCode, Legal Research and Public Benefits Bench.

Hy4 Preview is a reasoning model with a 1M-token context window and 64k max output tokens, priced at $0.83 per million input tokens and $2.50 per million output tokens. We accessed it through OpenRouter.

Congrats to the Tencent team on the release!