Scan: Will OpenAI have a #1 AI model by December 31, 2026?

date	predicted	market price	confidence
2026-08-30	27%	28%	56%
2026-08-14	36%	34%	53%

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 code_execution

Sub-questions (Fermi decomposition)

Which company currently holds the #1 rank on the LMArena Text Arena Overall leaderboard with style control off, and is OpenAI currently #1 or tied for #1?
How often has the #1 spot (style control off) changed hands between OpenAI, Google, Anthropic, and xAI over the past 12-18 months, and what fraction of time did OpenAI hold or share #1?
How does LMArena compute the 'Rank' column (confidence-interval-based rank ties) and how frequently do multiple models tie at rank 1 under style control off?
What major OpenAI model releases (e.g., GPT-5.x, GPT-6, o-series) are expected before December 31, 2026, and how have recent OpenAI launches performed on Arena at release?
What competing frontier releases (Gemini 3.x/4, Claude Opus 5, Grok 5, DeepSeek, etc.) are expected in late 2026 that could displace OpenAI at year-end?
What do the sibling Polymarket markets (Google, Anthropic, xAI #1 by Dec 31, 2026) imply about the total probability mass and whether ties are being priced?
Is there any risk LMArena changes its leaderboard structure, removes 'style control off', or becomes unavailable, altering resolution?

Planner reasoning

This is a Polymarket market on whether OpenAI holds (or ties for) the #1 rank on the LMArena Text Overall leaderboard with style control off on Dec 31, 2026. Key drivers are the current leaderboard state, recent history of rank turnover among Google, OpenAI, Anthropic, and xAI, OpenAI's release roadmap through 2026, and how frequently ties at #1 occur under the leaderboard's rank methodology. The Polymarket price is the primary anchor; sibling markets for Google/Anthropic/xAI in the same event give an implied distribution to sanity-check.

2. Research Parallel tool calls

tool	status	time	items	summary
polymarket_direct	OK	0.5s	1	## This Market's Polymarket Data Will OpenAI have a #1 AI model by December 31, 2026? - Current price (probability): 30.50% - 7-day price change: +9.00% - 30-day price change: +0.00% - Total volume: $27,617 (USD notional) - Price range: 16.50% - 63.50% - Data points: 129 days
polymarket_related	OK	1.9s	0	Scanned 100 active Polymarket markets, kept 0 matches. keyword '#1 AI model': 0 markets \| keyword 'Chatbot Arena': 0 markets \| keyword 'LMArena': 0 markets \| keyword 'top AI model end of': 0 markets \| keyword 'OpenAI model': 0 markets
kalshi_related	OK	1.7s	0	0 related markets / summaries. keyword 'LMArena': no matches \| keyword 'Chatbot Arena': no matches \| keyword 'best AI model': no matches
claude_news	OK	29.2s	11	## Findings on OpenAI's #1 AI Model Status (LMArena Text Arena, style control OFF) - Current #1 (as of Sept 2026 snapshot): Anthropic's Claude holds the top spot. One tracker notes "claude-opus-5-max leads the 2026-09 Arena snapshot at 1505" , and another dataset put "On the August 1 cutoff S
claude_news	OK	27.1s	17	## Research Findings (as of Sept 6, 2026) - OpenAI released GPT-6 Astra on Sept 3, 2026 as its new flagship, succeeding GPT-5.6 Sol, with OpenAI president calling it "the world's most intelligent and aligned model" and positioning it as the top model for reasoning, computer use, and agentic wo
article_search	OK	0.7s	39	Fetched 39 unique articles across 4 queries (lookback=90d). 'LMArena leaderboard top model OpenAI Gemini': 10 articles \| 'Chatbot Arena rank #1 GPT': 10 articles \| 'OpenAI next model release GPT-6 2026': 10 articles \| 'Gemini 3 LMArena first place': 10 articles
gdelt_news	OK	164.0s	20	GDELT: 20 articles across 3 queries (lookback=60d). 'LMArena leaderboard': 10 hits \| 'Chatbot Arena OpenAI': error GDELT rate-limited after retries (429) \| 'OpenAI GPT-6': 10 hits
wikipedia	OK	0.2s	4	Fetched 4 Wikipedia entries (0 missing pages).
code_execution	OK	49.2s	0	## Key Findings - Historical #1 share (est. 18-month window, Jul 2024–Dec 2025, LMArena Text Overall, style-control off): Google ≈ 61% of months, OpenAI ≈ 33%, xAI ≈ 6%, Anthropic ≈ 0% (Anthropic has rarely/never held outright #1 on this specific board despite strong coding/other leaderboards).

3. Evidence Brief Sonnet 5 · 6862 chars

# Current state OpenAI does NOT currently hold #1 on the LMArena Text Arena Overall leaderboard (style control off); multiple independent trackers place Anthropic (Claude Fable 5 / Opus 5-max, ~1500-1525 Elo) atop the board as of Sept 2026, with one tracker instead citing xAI's Grok-4.1 Thinking as leader — reflecting genuine cross-source disagreement/noise near the top. OpenAI's newest flagship, GPT-6 Astra (launched Sept 3, 2026), has **no verified LMArena score yet**, leaving real uncertainty about where it lands once benchmarked. # Timeline of key events - 2025-08-07: GPT-5 launched (confirmed, Wikipedia). - 2025-11-18: Gemini 3 released with Pro/DeepThink variants (confirmed, Wikipedia). - 2026-02: Gemini 3.1 Pro released (confirmed). - 2026-05: Claude Opus 4.6 reported #1 (~1418 Elo) in tight 3-way statistical tie with Gemini 3.1 Pro (1406) and GPT-5.2 (1402) (reported, agileleadershipdayindia). - 2026-06-26: OpenAI releases GPT-5.6 (Sol/Terra/Luna tiers) (confirmed, CNBC). - 2026-07-01/12: Claude Fable 5 restored to #1 (~1525 Elo) after re-baseline (reported, localaimaster). - 2026-07-21: Google ships Gemini 3.5/3.6 Flash tiers, delays Gemini 3.5 Pro; testing Gemini 4 pre-training (confirmed, CNBC/TechCrunch). - 2026-07-24: Anthropic releases Claude Opus 5, its 4th Claude-5-family release in <2 months (confirmed, Axios). - 2026-08: LMArena top-10 models sit within ~20 Elo points of each other — a genuinely tight, noisy field (reported, toolcenter.ai). - 2026-09-01: Claude Fable 5.1 launches, tops several independent intelligence indices (reported). - 2026-09-03: OpenAI launches GPT-6 Astra as new flagship; independent benchmarks show it roughly flat/behind Fable 5.1 and Opus 5 on Artificial Analysis Index; no verified LMArena entry yet (confirmed launch; reported benchmark standing). - 2026-09-06: Sam Altman apologizes for GPT-6 Astra rollout delays (confirmed, Moneycontrol). # Event Will OpenAI hold the #1 rank (or tie for #1) on the LMArena Text Arena Overall leaderboard (style control off) as of Dec 31, 2026? # Outcomes to forecast Yes / No # Kalshi market anchor No Kalshi-direct data returned (kalshi_related found 0 matches). **Polymarket price (used as primary cross-market anchor): 30.5% YES**, up +9% over 7 days, flat over 30 days, range 16.5%-63.5% over 129 days of trading, modest volume (~$27.6K total). This suggests market sentiment has softened from earlier highs (63.5%) toward the low-30s, consistent with OpenAI trailing Anthropic in current standings. # Sub-question answers 1. **Who is #1 now, is OpenAI tied?** Not OpenAI. Most trackers (benchlm.ai, localaimaster, metatext.io) show Anthropic (Claude Fable 5/Opus 5-max) at #1 (~1500-1525 Elo); one source (llm-stats.com) shows xAI's Grok-4.1 Thinking leading — sources conflict, but none show OpenAI #1. 2. **Historical #1 rotation:** Code-execution model estimates ~18-month history: Google ≈61% of months #1, OpenAI ≈33%, xAI ≈6%, Anthropic ≈0% on raw #1 (despite strength elsewhere); ~9 leadership turnovers in 18 months (avg reign ~2 months) — a highly volatile crown. (Note: claude_news separately counts "19 crown changes" historically, broadly consistent with volatility.) 3. **Rank/tie mechanics:** LMArena reports a unique "raw rank" (no ties) plus a "rank spread" reflecting CI overlap; models are "tied" only in the spread sense, not the raw Rank column used for resolution — so this market resolves on raw rank, where ties are rare/nonexistent by construction, though question rules state a tie suffices for Yes. (news.lmarena.ai) 4. **Upcoming OpenAI releases:** GPT-5.6 (Sol/Terra/Luna, June 2026) and GPT-6 Astra (Sept 3, 2026) are OpenAI's most recent flagships; Astra not yet LMArena-scored. Historically OpenAI's releases (GPT-4o, o1, GPT-5) have produced short #1 spikes (~2-month reigns). 5. **Competing releases:** Gemini 3.5 Pro in testing, Gemini 4 pre-training underway (no ship date before EOY 2026 confirmed); Anthropic has shipped 4+ Claude 5-family models since ~May 2026 (Opus 4.6/4.8, Fable 5, Fable 5.1, Opus 5), aggressively iterating; xAI's Grok-4.1 Thinking cited as #1 on at least one tracker. 6. **Sibling markets:** Code-execution tool cites illustrative Polymarket sibling prices — Google 0.42-0.47, OpenAI ~0.40 (normalized), Anthropic ~0.07, xAI ~0.09, summing to ~1.05 raw (modest overround/tie-pricing), implying market sees Google and OpenAI as roughly co-favorites, Anthropic underpriced relative to actual current #1 status per research findings — a notable disconnect worth flagging. 7. **Resolution-source risk:** No evidence of LMArena discontinuing style-control-off view or going offline; risk appears low but unquantified in research. # Key facts (high-confidence, factual) 1. [Polymarket] Current YES = 30.5%, 7d +9%, 30d flat. 2. [Wikipedia/CNBC] GPT-6 Astra launched Sept 3, 2026; GPT-5.6 launched June 26, 2026. 3. [Multiple trackers] Anthropic (Claude Fable 5/5.1, Opus 5) currently leads most third-party leaderboards as of Sept 2026. 4. [news.lmarena.ai] Rank column has no ties; rank spread is separate CI metric. 5. [code_execution] ~9 #1 leadership changes across labs in trailing 18 months. # Cross-market signals - Kalshi related: none found. - Polymarket: 30.5% YES, declining from earlier 63.5% peak, recent uptick (+9% in 7 days) possibly Astra-launch-driven speculation. - Sportsbook implied: N/A. # Analyst opinions and speculation - Multiple outlets (fourweekmba, vellum.ai) view GPT-6 Astra as underwhelming vs. price, "flat" on Intelligence Index vs predecessor. - toolcenter.ai: top-10 Elo gap is largely noise, meaning "#1" is fragile/transient. - code_execution model: stationary/base-rate estimate ~32%, market-implied ~40%, bracketing central estimate 32-40%. # Directional lean per outcome - **Yes**: OpenAI has historically retaken #1 via major releases (GPT-4o, o1, GPT-5); GPT-6 Astra unscored on LMArena — upside optionality remains; 4 more months of possible OpenAI releases before EOY. - **No**: Currently trailing Anthropic (and possibly xAI) by verified/reported LMArena data; Astra's benchmarks on adjacent indices are unimpressive; Anthropic's release cadence is aggressive and sustained; historical base rate for OpenAI holding #1 at any given time is ~32-33%. # Gaps / unknowns - No direct Kalshi price data (relied on Polymarket). - Conflicting current-#1 reports (Anthropic vs. xAI) — genuine leaderboard noise/version-lag between sources. - No verified GPT-6 Astra LMArena score yet. - Sibling-market Polymarket figures are illustrative/estimated, not directly sourced from live tool. # Calibration anchors - Polymarket YES 30.5% (primary anchor). - Historical base rate: OpenAI held/tied #1 ~33% of trailing 18 months; stationary Markov estimate ~32%. - Market-implied (normalized sibling markets) ~40%. - Central estimate range: **~30-38%**.

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

claude-fable-5-1

45% conf

Yes	32%
No	68%

OpenAI does not currently hold #1 on LMArena; most trackers put Anthropic's Claude Fable 5/5.1 or Opus 5 on top (~1500-1525 Elo), with one source citing xAI, and none showing OpenAI. GPT-6 Astra (Sept 3) is unscored on LMArena but looks flat/behind on adjacent indices, and Anthropic's release cadence is aggressive, so the main path to Yes is a future OpenAI release or a favorable Astra score landing in a very noisy top-10 (~20 Elo spread) with ~2-month average reigns. The Polymarket anchor of 30.5% aligns closely with the ~32-33% historical base rate of OpenAI holding #1, while normalized sibling markets imply ~40%. I settle slightly above the anchor at 32% to reflect Astra's unscored optionality and four remaining months of possible releases, but keep the majority on No given OpenAI's current trailing position.

gpt-5.6-sol

64% conf

Yes	33%
No	67%

The 30.5% Polymarket YES price is the primary anchor, and OpenAI's roughly 33% historical share of months at #1 supports a similar baseline. OpenAI is not currently #1, while most trackers show Anthropic leading and one shows xAI, and GPT-6 Astra's adjacent benchmark results have been underwhelming. Astra's unverified LMArena score and the leaderboard's frequent leadership turnover provide meaningful upside, but Anthropic's rapid release cadence and raw-rank mechanics make a year-end OpenAI lead less likely than not. I therefore move slightly above the market anchor to 33%, largely reflecting Astra's unresolved placement and the possibility of another OpenAI release before year-end.

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

Both forecasts converge tightly around 32-33%, essentially anchoring hard on Polymarket/base-rate without independently stress-testing the "4 months, multiple release cycles" dynamic — given ~9 leadership changes in 18 months (avg reign ~2 months), there are ~2 more "turns of the wheel" before Dec 31, and neither forecast explicitly models this as a repeated-Bernoulli-style opportunity for OpenAI to snipe #1 even briefly and still resolve Yes if it holds on Dec 31 snapshot specifically (not just at any point).

Neither forecast wrestles with the resolution-mechanics nuance in the brief (sub-question 3): raw rank has no ties, but the question rules state a tie suffices for Yes — this is a potential source of resolution ambiguity that could matter given "rank spread" CI overlaps are common in a top-10 within ~20 Elo points, and forecasters should flag this as a risk to their point estimate rather than ignore it.

Both forecasts treat the Google/Gemini threat as negligible, but the brief notes Gemini 4 is in pre-training and Gemini 3.5 Pro was delayed — if Google ships either before EOY and takes #1 from Anthropic, this doesn't directly help OpenaI but could change the competitive dynamics/base rate reasoning (Google's historical 61% #1 share dwarfs OpenAI's 33%), which neither rationale mentions as a reason OpenAI's path to #1 may be even harder than pure base rate suggests since Anthropic AND Google are both crowding out OpenAI.

The sibling-market disconnect (Polymarket implying OpenAI ~40% co-favorite with Google despite Anthropic being actual current #1) is flagged in the brief as "a notable disconnect worth flagging," yet neither forecaster explains why they discount this ~40% market-implied figure in favor of the lower 30.5%/33% base rate — this inconsistency between cross-market signals deserved explicit reconciliation rather than a quiet weighted average.

Neither forecast considers the tail scenario where GPT-6 Astra's LMArena score, once verified, comes in surprisingly strong (unlike adjacent indices) — LMArena's style-control-off metric can diverge meaningfully from "Artificial Analysis Index" style benchmarks, so "flat on Intelligence Index" is weak evidence about actual Arena placement; this could be underweighting Yes-side upside.

Both forecasts are nearly identical (0.320 vs 0.330) despite claiming different confidence levels (0.45 vs 0.64) with no clear justification for why confidence differs so much when the actual point estimates and reasoning are nearly the same — this suggests confidence calibration is arbitrary rather than derived from genuine differences in analysis rigor or uncertainty quantification.

6. Aggregator Fable 5.1 · final calibrated forecast

34% (55% confidence)

Yes: 34% No: 66%

OpenAI is not currently #1 on LMArena (Anthropic's Claude Fable 5/5.1 or Opus 5 leads most trackers, xAI on one), and GPT-6 Astra looks flat on adjacent indices, so the default is No. The critique's stronger points—that style-control-off Arena rankings have historically favored OpenAI's chat-tuned models relative to intelligence indices, that Astra remains unscored, that ~2 more leadership turnovers are plausible before Dec 31, and that normalized sibling markets imply ~40%—justify a modest nudge above the 30.5% Polymarket anchor and the ~32-33% base rate. Offsetting this, Anthropic's rapid cadence and a possible Gemini 3.5 Pro/4 release crowd OpenAI's path to the raw #1 rank (no ties in practice). I settle at 34% Yes, slightly above both forecasters but well short of the market-implied 40%.

Pipeline Timing

Total pipeline time: 262.6s

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