Scan: Will Anthropic have the best AI model on LiveBench (Mathematics) at the end of September 2026?

1. Planner Fable 5.1 · Fermi decomposition + tool plan

Tools chosen: polymarket_direct polymarket_related kalshi_related claude_news claude_news article_search gdelt_news wikipedia

Sub-questions (Fermi decomposition)

Which company's model currently holds the top Mathematics score on LiveBench.ai, and what is the gap between Anthropic's best model and the leader?
Has Anthropic released or is it expected to release a new frontier model (e.g., Claude Opus/Sonnet successor) before September 30, 2026, and how have recent Claude models scored on LiveBench Mathematics relative to OpenAI/Google/xAI models?
Are OpenAI, Google, xAI, DeepSeek, or others expected to release new frontier models before the end of September 2026 that would likely top the Mathematics category?
How frequently does LiveBench release new question sets and how much do rankings in the Mathematics category change between releases?
Historically, how often has Anthropic held #1 on LiveBench Mathematics (vs. OpenAI/Google), given Claude models have tended to lead coding rather than math categories?
What do the sibling markets in this Polymarket group (OpenAI, Google, xAI, Other) imply, and do they sum consistently with the Anthropic price?

Planner reasoning

This is a Polymarket question about which lab tops LiveBench's Mathematics category on Sept 30, 2026. Key drivers are the current leaderboard standings (who leads Mathematics now and by what margin), the release cadence of frontier models from Anthropic vs OpenAI, Google, xAI, and others before the end of September, and how LiveBench refreshes its question sets (which can reshuffle rankings). The market price is the primary anchor; news on imminent model launches and current leaderboard data are the main updates.

2. Research Parallel tool calls

tool	status	time	items	summary
polymarket_direct	OK	0.3s	1	## This Market's Polymarket Data Will Anthropic have the best AI model on LiveBench (Mathematics) at the end of September 2026? - Current price (probability): 90.50% - 7-day price change: +50.00% - 30-day price change: +55.00% - Total volume: $15,316 (USD notional) - Price range: 21.50% - 94.50
polymarket_related	OK	2.9s	0	Scanned 100 active Polymarket markets, kept 0 matches. keyword 'LiveBench': 0 markets \| keyword 'best AI model': 0 markets \| keyword 'Anthropic': 0 markets \| keyword 'Claude': 0 markets
kalshi_related	OK	2.6s	1	1 related markets / summaries. keyword 'LiveBench': no matches \| keyword 'best AI model': no matches \| keyword 'Anthropic Claude': ok
claude_news	OK	22.8s	6	Based on available search results, here are the key findings (note: many aggregator sites show inconsistent/unverified data, and LiveBench's official site was not directly scraped, so confidence is moderate): - Most direct evidence: A September 2026 roundup states that the best AI for hard pro
claude_news	OK	22.9s	10	Key findings from research on frontier AI model math benchmark standings (Aug-Sept 2026): - LiveBench Mathematics leader is NOT Anthropic as of September 2026: felloai.com's September 2026 rankings state the best AI for hard problem solving is GPT-5.6 Sol, taking #1 on LiveBench Mathematics at
article_search	OK	0.6s	36	Fetched 36 unique articles across 4 queries (lookback=45d). 'LiveBench leaderboard mathematics top model': 10 articles \| 'Anthropic Claude new model release September 2026': 10 articles \| 'OpenAI GPT new model math benchmark': 10 articles \| 'Gemini Grok new model release math': 10 articles
gdelt_news	OK	152.0s	30	GDELT: 30 articles across 3 queries (lookback=30d). 'LiveBench leaderboard': 10 hits \| 'Anthropic Claude release': 10 hits \| 'Claude Opus mathematics benchmark': 10 hits
wikipedia	OK	0.2s	3	Fetched 3 Wikipedia entries (0 missing pages).

3. Evidence Brief Sonnet 5 · 7660 chars

# Current state As of the research cutoff (~Sept 2026), multiple independent trackers (felloai.com, benchlm.ai) report OpenAI's GPT-5.6 Sol at #1 on LiveBench Mathematics (96.2), while Anthropic's flagship math-tested model (Claude Opus 4.5) ranked #6 of 7 (58.3/100) as of August 2026. Resolution occurs on a single check of livebench.ai on 2026-09-30 12:00 ET — no averaging, only the snapshot at that moment matters, and a late-September Anthropic release (if any) could still flip this. # Timeline of key events - 2025 (ongoing) — Claude models have historically led *coding* (SWE-bench) and *language* categories on LiveBench, not Mathematics — confirmed pattern per multiple sources (llm-stats.com, felloai.com). - 2026-07-24 (reported) — Anthropic releases Claude Opus 5; swfte.com's composite index (MMLU Pro/HumanEval/MATH blend, not LiveBench) names it a new "frontier #1," but no LiveBench Math claim attached. - 2026-08 (reported) — Claude Opus 4.5 scores 58.3/100 on LiveBench Math, ranked 6th of 7 eligible models (benchlm.ai). - 2026-08-20 (reported) — Memeburn compares "GPT-5.6 Sol vs Claude Opus 5" benchmarks, framing OpenAI as the challenger to beat on hard reasoning/math. - 2026-09 (reported, ~early Sept) — Anthropic releases Claude Fable 5 / 5.1; leads LiveBench *Language* (90.7) and SWE-bench Verified (0.950), but no Math-leadership claim found. - 2026-09 (reported) — felloai.com and benchlm.ai September rankings both name OpenAI's GPT-5.6 Sol (96.2) as LiveBench Math #1; benchlm.ai alternatively names Kimi K2.6 as "current math leader" in a separate framing — no Anthropic model cited as math leader in either source. - 2026 (undated, last 41 days per Polymarket data) — Polymarket price for this exact market surges from a low of 21.5% to 90.5%–94.5%, a +50-55% move in 7/30 days, on thin volume (~$15.3k total). # Event Will Anthropic have the best AI model on LiveBench (Mathematics) at the end of September 2026 (checked 2026-09-30 12:00 ET)? # Outcomes to forecast Yes / No (binary; resolves "No" unless an Anthropic model tops the LiveBench Mathematics leaderboard at check time). # Kalshi market anchor No Kalshi-direct quote was returned for this specific ticker (kalshi_related returned only unrelated Anthropic markets, e.g., IPO race at 96%). The only direct market quote available is Polymarket's own price for this identical event: **90.5% YES**, up sharply from a 30-day/7-day low of 21.5%, trading in a 21.5%–94.5% range over 41 data points, total volume only ~$15,316 (thin/possibly noisy). This steep +50-55pt swing conflicts sharply with the qualitative benchmark evidence below (see Gaps). # Sub-question answers 1. **Current Mathematics leader & gap to Anthropic** — OpenAI's GPT-5.6 Sol reportedly leads at 96.2 (felloai.com, Sept 2026); Anthropic's Opus 4.5 scored 58.3/100 (#6 of 7) as of Aug 2026 (benchlm.ai) — a large gap. No source shows a Claude model in the top spot for Math specifically. 2. **Anthropic frontier releases & relative math scores** — Anthropic released Claude Opus 5 (~2026-07-24) and Claude Fable 5/5.1 (~Sept 2026); these lead Language and SWE-bench Verified categories, not Math. Opus 4.6 reportedly hits 94.2% on MATH (a different benchmark) but Anthropic's own marketing emphasizes coding/agentic strength, not math supremacy (datacamp.com, claude5.ai). 3. **Competitor frontier releases** — OpenAI (GPT-5.6 Sol, GPT-5.4), Google (Gemini 3.1 Pro, "strong math"), and possibly Moonshot's Kimi K2.6 are cited as math leaders/contenders in Sept 2026 rankings; xAI's Grok 4.6 released mid-Aug 2026 with benchmark claims of uncertain #1 status. No article confirms Anthropic overtaking these on Math specifically. 4. **LiveBench release cadence / ranking volatility** — Not directly answered by research; general AI-benchmark commentary notes rapid model churn (new releases roughly every 4-8 weeks across labs in 2026), implying rankings can shift before the Sept 30 snapshot, but no LiveBench-specific cadence data was found. 5. **Historical Anthropic #1 rate on LiveBench Math** — Not quantified, but consistent qualitative pattern: Claude models "have tended to lead coding rather than math categories" (multiple sources); no historical instance of Anthropic #1 in Math found in this research. 6. **Sibling markets / consistency** — polymarket_related found zero matching sibling markets (OpenAI/Google/xAI/Other variants not located), so cross-market consistency cannot be verified from this research. # Key facts (high-confidence, factual) 1. [felloai.com, Sept 2026] GPT-5.6 Sol (OpenAI) cited as LiveBench Math #1 at 96.2. 2. [benchlm.ai] Claude Opus 4.5 ranked #6/7 on LiveBench Math at 58.3/100 (Aug 2026). 3. [benchlm.ai] Math is "saturated" and carries only ~5% weight in LiveBench's composite; AIME/HMMT largely solved across frontier models. 4. [Polymarket] This exact market priced 90.5% YES, up from 21.5% low, on ~$15.3k total volume (thin). 5. [Wikipedia] Anthropic's model lineup by Sept 2026 includes Opus 5, Fable 5/5.1, Sonnet 5; company emphasis is safety/coding/agentic, not math. # Cross-market signals - Kalshi related: No direct sibling found; unrelated Anthropic markets (IPO race, US equity stake) don't inform Math leaderboard odds. - Polymarket: Same-market price 90.5% YES — strongly diverges from qualitative benchmark evidence pointing to OpenAI leading Math. - Sportsbook implied: N/A. # Analyst opinions and speculation - Multiple AI-news aggregators (felloai.com, benchlm.ai) independently converge on OpenAI (or possibly Kimi K2.6) as Math leader, not Anthropic — moderate confidence, some inconsistency/staleness flagged in sourcing (llm-stats.com data looked outdated). - Anthropic's own product positioning (Opus 4.5/4.6, Fable 5) consistently centers on coding and agentic capability rather than math supremacy claims. # Directional lean per outcome - **Yes (Anthropic)**: Supported only by Polymarket's own sharp price rally (90.5%) and Anthropic's rapid Opus 5/Fable 5.1 release cadence, which *could* still deliver a math-focused leap before Sept 30. No direct benchmark evidence supports this. - **No (not Anthropic)**: Supported by essentially all qualitative benchmark evidence — GPT-5.6 Sol reportedly at 96.2 vs. Claude Opus 4.5 at 58.3 (#6/7); Anthropic's stated strengths are coding/language, not math. # Gaps / unknowns - Critical unresolved conflict: benchmark research strongly implies "No," while the market itself (the exact ticker) prices "Yes" at 90.5% with high momentum — this is a major red flag requiring resolution before trusting either signal; volume is thin ($15k), so the price move may reflect low-liquidity noise, insider info, or a recent (unreported) Anthropic math breakthrough not captured by the aggregator snapshots used. - No direct scrape of official livebench.ai Mathematics table was obtained in this research; all evidence is secondhand via aggregators of uncertain reliability (felloai, benchlm, swfte flagged as internally inconsistent). - No LiveBench release-cadence data to gauge how stable rankings are through Sept 30. - Sibling markets (OpenAI/Google/xAI variants) could not be located to cross-check probability consistency. # Calibration anchors - Polymarket current YES price for this exact market: 90.5% (anchor, but conflicts with qualitative evidence). - Aggregator-reported gap: OpenAI 96.2 vs. Anthropic Opus 4.5 58.3 on LiveBench Math — a large, structurally significant gap if accurate. - Historical base rate: Anthropic models have not been reported as LiveBench Math #1 in any cited source; base rate for Anthropic leading this specific category appears low historically.

4. Forecasters Fable 5.1 + GPT-5.6 Sol · in parallel

claude-fable-5-1

33% conf

Yes	72%
No	28%

The only direct market quote for this exact event is Polymarket at 90.5% YES, having surged from 21.5% — a move of that size on the exact ticker usually reflects an observed leaderboard change (e.g., a new Anthropic model topping LiveBench Math) rather than noise, even on thin ~$15k volume. The contrary evidence in the brief (GPT-5.6 Sol at 96.2, Opus 4.5 at 58.3/#6) comes from secondhand aggregators flagged as internally inconsistent and possibly stale, and none directly scraped livebench.ai. Historically Claude has led coding/language rather than math, and the resolution is a single snapshot vulnerable to a late competitor release, so I discount the market somewhat toward No. Net: lean Yes at ~72%, well below the market but far above what the stale aggregator data alone would imply.

gpt-5.6-sol

43% conf

Yes	38%
No	62%

The current-leader evidence points toward No because GPT-5.6 Sol reportedly leads Mathematics at 96.2, while the latest cited Anthropic score is 58.3 and no source identifies Anthropic as the category leader. Anthropic’s recent releases and historical profile also point toward No: reported leadership is in coding and language, while OpenAI, Google, and Kimi remain the cited math contenders. Rapid model churn leaves room for a late release to flip the single snapshot, but the brief provides no LiveBench-specific release evidence or documented Anthropic math breakthrough. I anchor on the identical Polymarket’s 90.5% Yes price but discount it heavily because its sharp move occurred on only about $15,300 of volume and conflicts with all available benchmark evidence; lacking a direct official LiveBench scrape prevents a stronger No forecast.

5. Devil's Advocate Sonnet 5 · red-team critique

Both forecasters treat the 90.5% Polymarket price as a meaningful anchor despite explicit evidence it's "thin/possibly noisy" ($15.3k volume) — Forecast 1 in particular over-weights this by landing at 72% Yes, nearly reversing the qualitative evidence (Opus 4.5 at 58.3, #6/7) on the theory that the price move "usually reflects an observed leaderboard change," which is speculation not supported by any cited source confirming an Anthropic math breakthrough.

Neither forecaster adequately addresses the "math is saturated, ~5% weight in composite" fact (benchlm.ai) — this suggests ties/near-ties at the top are plausible and a single new release could plausibly saturate the benchmark, which should raise volatility-driven Yes probability somewhat, but neither uses this to justify their number quantitatively.

Both forecasters ignore the alternative explanation for the Polymarket surge: thin-volume markets can be moved by a single large speculative bet or manipulation, and with only $15.3k total volume, a handful of trades could produce a 50+ point swing unrelated to fundamentals — this "noise" hypothesis deserves more explicit weight than either gives it, especially Forecast 1 which dismisses it too quickly.

Neither forecaster discusses the base-rate fact explicitly stated in the brief: "no historical instance of Anthropic #1 in Math found in this research" — this is a strong prior that should anchor forecasts closer to the qualitative evidence (low Yes) unless there's concrete evidence of a specific late-September release with math claims, which neither model successfully identifies for Anthropic (Fable 5.1 is confirmed to lead Language/SWE-bench, not Math).

Forecast 2's 38% Yes is inconsistent with its own analysis — it states "the current-leader evidence points toward No" and lists multiple confirmatory facts, yet still assigns nearly 2-in-5 odds to Yes, seemingly anchored too heavily on the Polymarket price despite calling it noisy; this gap between stated reasoning and final number is not well justified.

Neither forecaster considers that the "Yes" resolution requires Anthropic to be strictly #1 (not just improved), meaning even a large Anthropic math jump might still leave them behind OpenAI's 96.2 or Google's Gemini 3.1 Pro "strong math" claims — the bar for Yes is higher than merely "Anthropic releases a new model," which both forecasts somewhat conflate.

6. Aggregator Fable 5.1 · final calibrated forecast

68% (38% confidence)

Yes: 68% No: 32%

The only direct signal on this exact event is Polymarket at 90.5% YES after a surge from 21.5%; for benchmark-leaderboard markets, traders typically check livebench.ai directly, so a move of this size more plausibly reflects an observed leaderboard change (e.g., a recent Anthropic release topping Math) than pure noise, even at $15k volume. The contrary evidence is secondhand and stale: the 58.3 score is for Opus 4.5, superseded by Opus 5 and Fable 5/5.1, and the aggregators (felloai, benchlm) are flagged as internally inconsistent, with no direct scrape of the official table. I still discount the market materially because the critique is right that thin markets can be moved by a few trades, Anthropic has no historical record of leading LiveBench Math, and the single-snapshot resolution is exposed to a late competitor release (OpenAI, Google, Kimi) that could retake #1. Net: lean Yes at ~68%, closer to Forecast 1 but with more weight on the noise and reversal risks than it allowed.

Pipeline Timing

Total pipeline time: 268.3s

Per-tool research timings shown in the Research section above.