BenchLM recommendation
Best Proprietary LLMs in 2026
As of July 20, 2026, the top model in best proprietary llms on the BenchLM leaderboard is Claude Mythos 5 with a score of 83.9.
Last verified: July 20, 2026
Top proprietary/closed-source AI models ranked by benchmark performance.
Unless noted otherwise, ranking surfaces on this page use BenchLM's provisional leaderboard lane rather than the stricter sourced-only verified leaderboard.
Bottom line: Claude Fable 5 leads proprietary models overall, with Gemini 3.1 Pro and GPT-5.4 close behind. The top tier is competitive — choice often comes down to pricing, latency, and API ecosystem.
Claude Mythos 5 leads this ranking with a score of 83.9, followed by Claude Fable 5 (83.7) and GPT-5.6 Sol (82). The top three are separated by just a few points — any of them would perform well for this use case.
All models in this ranking are proprietary. No open-weight alternatives are available for this category.
This ranking is based on provisional overall weighted scores across BenchLM.ai's scoring formula tracked by BenchLM.ai. For detailed model profiles, click any model name below. To compare two specific models head-to-head, use the "vs #" links.
What changed
Claude Fable 5 entered at #1 across proprietary models with the highest overall score.
Gemini 3.1 Pro strong #2 among proprietary models — best non-reasoning option.
GPT-5.4 leads knowledge benchmarks at 98 and holds a strong #3.
How to choose
Best proprietary model regardless of cost?
Claude Fable 5 — highest overall score
Best without chain-of-thought?
Gemini 3.1 Pro — top non-reasoning proprietary
Knowledge and factual accuracy?
GPT-5.4 — leads knowledge benchmarks at 98
Cost-effective proprietary?
Gemini 3.1 Pro — strong scores at competitive pricing
Full Rankings (113 models)
Key Takeaways
The top model is Claude Mythos 5 by Anthropic with a BenchAlign v5 score of 83.9 and Supported evidence.
113 models are included in this ranking.
Score in Context
What these scores mean
Models are ranked by the same overall BenchLM score used across all leaderboards. Comparing within proprietary's lineup helps identify which model fits your use case and budget.
Known limitations
This page only shows proprietary models. Cross-provider comparison requires the overall or category-specific leaderboards. Newer models may have limited benchmark coverage initially.
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