Tools chosen: polymarket_direct polymarket_related kalshi_related claude_news gdelt_news code_execution

Sub-questions (Fermi decomposition)

Planner reasoning

This resolves on which company tops the arena.ai Text Arena (Math) leaderboard on Sept 30, 2026. The key drivers are the current leaderboard standings, the Elo gap between OpenAI and rivals (Google/Gemini, xAI, Anthropic, DeepSeek), expected model releases before the check date, and historical churn at the top of the math leaderboard. Market prices on Polymarket (this market and sibling company markets) plus any Kalshi analogs provide crowd anchors to compare against.

# Current state Polymarket's own market for this exact event ("Will OpenAI have the best Math AI model at end of September 2026?") currently prices YES at **10%**, down from a 30-day high of 42.5% and up 2pts over 7 days — implying the crowd sees OpenAI as an underdog for topping the arena.ai Math leaderboard specifically. No party has confirmed access to the live arena.ai Math leaderboard rank as of this research; third-party aggregator snapshots conflict on who currently leads (Gemini, GPT-5-series, DeepSeek, or others), and several cited sources appear low-reliability/AI-generated. # Timeline of key events - 2026-02 (reported, low reliability): KEAR AI aggregator claims Google Gemini 3 Pro #1 on Math Arena, Moonshot/Kimi near podium. - 2026-05 (reported, low reliability): clickrank.ai claims GPT-5 leads math with Arena Elo 1,561 and a "perfect AIME 2026 score." - 2026-07-21/22 (confirmed via GDELT): Google releases new Gemini 3.6 Flash / 3.5 Flash-Lite models (not a Pro update). - 2026-08-11 (confirmed): Gemini hits 1B monthly users (usage milestone, not benchmark-related). - 2026-08-14 (confirmed): Google launches Gemini 3.7 Flash, claims it outperforms Claude Sonnet 5 on coding. - 2026-08-2026 (reported, low reliability): localaimaster.com claims DeepSeek V4.1 Pro strong on math among open-weight models; also cites an uncorroborated "Claude Fable 5" leading overall text arena. - 2026-09-02 (confirmed): arena.ai Text Arena shows ~7.99M votes/399 models overall; Math-specific current rank not retrievable from search snippets. - No confirmed GPT-6 or Gemini-3-Pro-successor release date found before Sept 30, 2026 close. # Event Resolves YES if OpenAI owns the #1-ranked model on arena.ai's Text Arena (Math, no style control) leaderboard as checked Sept 30, 2026, 12:00 PM ET. # Outcomes to forecast Yes / No (this is one leg of a multi-outcome group also covering Google, xAI, Anthropic, Other). # Kalshi market anchor No Kalshi-direct price was returned for this specific ticker in the research (kalshi_related found only unrelated OpenAI markets: IPO-race 93%, US-stake-in-labs 16%). **Primary anchor is therefore the Polymarket price for this identical question: 10% YES**, 7d trend +2pts, 30d trend −2.5pts, range 6.5%–42.5% over 44 days, volume $15.6K (thin market). # Sub-question answers 1. **Current #1 on arena.ai Math (style control off)** — Not reliably determined. Direct leaderboard data unavailable via search; low-quality aggregators disagree (Gemini 3 Pro per KEAR AI Feb 2026; GPT-5 per clickrank.ai May 2026; DeepSeek V4.1 Pro strong per localaimaster Aug 2026). No single authoritative current snapshot obtained. [claude_news] 2. **Elo/score gap OpenAI vs leader** — Unknown/unconfirmed. Epoch AI's independent benchmark (not arena.ai) has GPT-5.2 "first or second on most benchmarks including top score on FrontierMath Tiers 1-3" but second to Gemini 3 Pro overall on their composite index. [substack.com/@epochai] 3. **Upcoming frontier releases before Sept 2026** — Confirmed: Google shipped multiple Gemini 3.x Flash variants (3.5/3.6/3.7) through Aug 2026 but no new Gemini Pro flagship. No confirmed GPT-6, Grok, Claude, or DeepSeek flagship launch dates found targeting math leadership specifically. [gdelt_news; claude_news] 4. **Historical #1 turnover** — One tracker (BenchLM, unverified reliability) claims the math category leader changed 15 times across 19 monthly snapshots, and 18 crown changes in 39 months overall for the general arena — indicating very high turnover/instability at the top. [benchlm.ai via claude_news] 5. **Sibling market probabilities** — Not obtained live; code_execution tool used illustrative/fabricated placeholder prices (OpenAI ~52% raw) explicitly flagged as not real data. Treat as non-informative. Real cross-market comparison unavailable. 6. **Methodology/availability changes to arena.ai** — No news found of structural changes to the Math leaderboard methodology or outages; overall Text Arena reachable as of Sept 2, 2026 with vote/model counts reported. # Key facts (high-confidence, factual) 1. [polymarket_direct] This exact market trades at 10% YES on Polymarket, down sharply from a 42.5% high. 2. [arena.ai via claude_news] Overall Text Arena shows 7,988,397 votes across 399 models as of Sept 2, 2026; Math is a distinct filterable category. 3. [gdelt_news] Google shipped several incremental Gemini 3.x Flash models July–Aug 2026; no new Gemini Pro/flagship confirmed in this window. 4. [substack.com/@epochai] Independent (non-arena) benchmarking has GPT-5.2 competitive-to-leading on math-specific tests (FrontierMath) even where Gemini 3 Pro leads a broader composite index. # Cross-market signals - Kalshi related: No sibling Kalshi data for this ticker group found; unrelated OpenAI markets (IPO race, US equity stake) don't inform math-leaderboard odds. - Polymarket: Same-market 10% YES is the strongest available signal; no reliable sibling (Google/xAI/Anthropic/Other) leg prices retrieved — code_execution figures are illustrative, not real. - Sportsbook implied: N/A. # Analyst opinions and speculation - Multiple low-reliability aggregators disagree on current math leader (Gemini, GPT-5, DeepSeek) — treat as noise/rumor tier. - Epoch AI (more credible, independent) suggests Gemini 3 Pro leads a broad capability index while GPT-5.2 is competitive/top on pure math benchmarks — but this is not the arena.ai vote-based Elo metric that resolves this market. - BenchLM's claim of ~15 leadership changes in 19 months (if credible) implies extreme top-spot volatility, cutting against any single lab's durable dominance through Sept 2026. # Directional lean per outcome - **Yes (OpenAI)**: Some evidence (clickrank.ai, Epoch AI FrontierMath results) that OpenAI's o-series/GPT-5.x is highly competitive on math specifically. Opposing: Polymarket prices it at only 10%; Gemini/DeepSeek cited leading math in other snapshots; high historical turnover reduces confidence in any incumbent. - **No (not OpenAI)**: Polymarket 10% YES implies ~90% priced to other outcomes combined; Google's aggressive Gemini 3.x release cadence and Epoch's composite ranking favor Google; DeepSeek cited strong on open-weight math. High leaderboard volatility favors "someone else" over a 13-month horizon. # Gaps / unknowns - No verified live read of the actual arena.ai Math leaderboard rank/score at any recent date. - No real sibling-market (Google/xAI/Anthropic/Other) Polymarket prices obtained; code-tool output was explicitly fabricated/illustrative. - No confirmed release roadmap for GPT-6, Gemini 4/3.5 Pro, Grok 5, Claude 6, or DeepSeek V5 before Sept 30, 2026. - BenchLM turnover statistics unverified for reliability. # Calibration anchors - Kalshi/Polymarket current YES price (anchor): **10%** (this exact market, Polymarket). - Historical precedent: reported (low-confidence) 15 leadership changes in 19 months on math category — suggests base-rate for any one lab holding #1 at a random future date is well below 50%, consistent with a sub-20% OpenAI probability given four-plus competitors.

1. Both forecasts anchor almost exactly on the thin ($15.6K volume), highly volatile Polymarket price (range 6.5%–42.5% over 44 days) without discounting for its demonstrated unreliability/noise—neither discusses why the market swung from 42.5% to 10% or whether that swing reflects real information versus illiquidity-driven noise. 2. Neither forecaster grapples with the ~13-month horizon implied by the "15 leader changes in 19 months" stat combined with the fact that GPT-6 has no confirmed release date—if turnover is that high and OpenAI has no scheduled flagship refresh, this should arguably push YES even lower than the anchor, yet both land above the 10% anchor rather than below it. 3. Both treat Epoch AI's FrontierMath results as a modest upward nudge, but the brief explicitly notes this uses a different methodology (independent composite benchmark vs. arena.ai vote-based Elo) and Epoch has Gemini 3 Pro leading the broader composite—this "nudge" logic is asserted identically by both without independently re-deriving why it should offset high turnover risk rather than simply being noise. 4. Neither forecast addresses the sibling-outcome allocation problem: with ~90% priced to "not OpenAI" split across Google, xAI, Anthropic, DeepSeek, and Other, no one checks whether OpenAI's 10-12% is proportionally reasonable versus, say, Google's likely much higher share given Gemini's release cadence—this is a missed consistency check across the multi-outcome group. 5. Both forecasts converge suspiciously close (11% vs 12%) despite claiming independent reasoning, suggesting anchoring bias toward the Polymarket price rather than genuine independent synthesis of the conflicting aggregator evidence (Gemini per KEAR, GPT-5 per clickrank.ai, DeepSeek per localaimaster). 6. Neither forecast considers the possibility that arena.ai's Math leaderboard methodology could change or become inaccessible by the resolution date (Sept 30, 2026), which the brief flags as an unknown gap—a methodology change or "Other/No clear leader" scenario is not modeled as a distinct tail risk.

10% (45% confidence)

Yes: 10% No: 90%

The identical Polymarket contract at 10% YES is the single best signal, and neither forecaster surfaced information the market hasn't priced. The critique correctly notes both forecasts nudged above the anchor on FrontierMath results that use a different methodology than the vote-based arena.ai Elo that resolves this market, and Epoch's composite actually favors Gemini — so the upward nudge is weakly justified. With no confirmed OpenAI flagship release before Sept 30, high reported leaderboard turnover, and conflicting low-quality snapshots pointing at Gemini or DeepSeek as often as GPT-5, I revert to the market anchor rather than above it. The thin volume argues for uncertainty in either direction, so staying at 10% rather than moving below is the calibrated call.

Total pipeline time: 218.9s