25% — Best AI in Dec 2026
Kalshi 25% · 8 contracts · $98K volume · medium confidence
Updated 2026-09-07 14:13:26 UTC

Why this matters:
This 19% probability reflects the likelihood that ChatGPT will be considered the best AI system as of December 31, 2026. The relatively low price compared to Claude (70¢) suggests market participants currently view Claude as the stronger performer. The probability is driven by two main dynamics: first, the pace of capability improvements across leading AI systems over the next four months, and second, how the AI research community and industry define "best" — whether based on benchmarks, real-world performance, or user adoption. The key uncertainty resolves on December 31, 2026, when market adjudicators will determine which system meets the resolution criteria, likely based on published benchmarks and performance evaluations released in late 2026.

Key factors:
- Claude's higher market price (70¢) versus ChatGPT (14¢) suggests traders currently favor Claude as the best-performing system
- ChatGPT maintains substantially higher trading volume ($12,307 in 24h) compared to other contracts, indicating significant market interest despite lower probability
- The four-month timeframe provides narrow window for major capability shifts, constraining the likelihood of dramatic repositioning among established players
- Resolution criteria and evaluation methodology are not explicitly defined, creating ambiguity about whether "best" reflects benchmark scores, real-world utility, or market leadership
- A September 2026 Claude contract exists at only 11¢, indicating traders expect further capability developments before year-end assessments

Contracts:
- Best AI in Sep 2026?: Gemini — 3¢ Kalshi $30K (weight 31%)
- Best AI on Dec 31, 2026?: ChatGPT — 25¢ Kalshi $26K (weight 27%)
- Best AI in Sep 2026?: Claude — 81¢ Kalshi $12K (weight 12%)
- Best AI on Dec 31, 2026?: Grok — 7¢ Kalshi $11K (weight 11%)
- Best AI in Sep 2026?: ChatGPT — 14¢ Kalshi $9K (weight 10%)
- Best AI on Dec 31, 2026?: Claude — 58¢ Kalshi $5K (weight 6%)
- Best AI on Dec 31, 2026?: Gemini — 6¢ Kalshi $4K (weight 4%)
- Best AI in Sep 2026?: Grok — 3¢ Kalshi $25 (weight 0%)

---

## Methodology

SimpleFunctions aggregates live YES-side prices from Kalshi and Polymarket contracts bound to this question. For binary topics the headline is the liquidity-weighted mid-price (weight = log(1 + 24h volume) × freshness, where freshness is 1.0 if updated <24h, 0.7 if <7d, 0.4 otherwise). For multi-outcome (winner-take-all) topics the headline is the current leader's price — disjoint outcomes are never arithmetically averaged. Snapshots refresh every 5 minutes during market hours.

## SF Signal

- SF Index, regime, and 30d Brier calibration are computed separately and surfaced at https://simplefunctions.dev/admin/calibration.
- No SimpleFunctions index / regime / calibration signal is bound to this topic yet — the headline above is market-derived only.

---

*Last verified: 2026-09-07T13:20:50.360Z*

By SimpleFunctions — https://simplefunctions.dev/

Cite as: "25% per prediction markets (SimpleFunctions, September 2026)"
Canonical: https://simplefunctions.dev/answer/llm1
Full data: https://simplefunctions.dev/api/public/query?q=Best%20AI%20in%20Dec%202026
Provider: SimpleFunctions — https://simplefunctions.dev