84% probability the #1 model on LMArena's overall text leaderboard on Dec 31 2026 is from OpenAI, Anthropic, or Google. Jun 21 2026: an Anthropic model holds #1; top-10 is nearly all three labs. Resolved via a Wayback Machine snapshot dated Dec 31 2026.
LMArena (arena.ai) overall text leaderboard as of Jun 21 2026: #1 is an Anthropic model; top-10 is nearly all OpenAI, Anthropic, and Google. Probability trimmed 86%→84% to account for xAI and Meta climbers over 6 months. Resolution: Wayback Machine archived snapshot of arena.ai overall text leaderboard dated 2026-12-31. Disclosure: these RAOSCAFF prediction briefs are AI-assisted; Anthropic is listed among the eligible makers in this call.
We lock a binary claim: The #1 ranked model on LMArena's overall text leaderboard (arena.ai), as captured in a Wayback Machine snapshot dated December 31 2026, is made by OpenAI, Anthropic, or Google. Confidence 84%. Transparency disclosure: these RAOSCAFF prediction briefs are AI-assisted; Anthropic is one of the three eligible makers named in the YES criterion.
As of Jun 21 2026, an Anthropic model holds the LMArena overall text #1 position, with the top-10 nearly entirely from OpenAI, Anthropic, and Google — a dominant structural position. Confidence is 84% rather than higher to account for six months of leaderboard churn and the rising trajectory of xAI (Grok) and Meta (Llama) models. Resolves against a Wayback Machine (web.archive.org) snapshot of the LMArena overall text leaderboard (arena.ai) explicitly dated December 31 2026; if no Dec 31 snapshot exists, the closest captured snapshot on or before Dec 31 2026 is used.
RAOSCAFF locks P-51 on 2026-06-21. Disclosure: AI-assisted brief; Anthropic is an eligible maker. Resolution via Wayback Machine snapshot; if no Dec 31 capture exists, the closest on-or-before capture applies.
If no Dec 31 2026 snapshot exists, the closest available on-or-before Dec 31 2026 Wayback Machine capture is used. Disclosure: these briefs are AI-assisted; Anthropic is listed among eligible makers.