36% — Who will be the Heavyweight Title on Dec 31, 2026
Leader: Tom Aspinall at 36% · Kalshi 36% · 4 contracts · $267 volume · medium confidence
Updated 2026-06-28 04:10:23 UTC

Tracks the leading outcome in a winner-take-all prediction market set with 4 outcomes.

Why this matters:
This 25% probability indicates roughly one-in-four odds that a specific fighter will hold the UFC Heavyweight Title on December 31, 2026. The current market leader reflects expectations based on the fighter's recent performance, injury status, and position in the title contention rankings. Movement in this probability would likely follow significant fight outcomes—wins advancing a contender toward a title shot, or losses eliminating them from contention. The primary catalyst for resolution will be championship fights scheduled between now and year-end; any injury, upset result, or title vacancy would substantially shift these odds. Secondary factors include interim title creations and unexpected retirements that could alter the competitive landscape.

Key factors:
- Current title holder's health status and scheduled title defense dates through December 2026
- Win-loss record and strength of schedule for leading contenders in the heavyweight rankings
- Historical frequency of title changes in the heavyweight division during comparable time windows
- Interim title creation likelihood, which could fragment the holder landscape
- Major injuries or retirements announced among top-5 ranked contenders

Contracts:
- Who will be the Heavyweight Title on Dec 31, 2026?: Tom Aspinall — 36¢ Kalshi $77 (weight 29%)
- Who will be the Heavyweight Title on Dec 31, 2026?: Ciryl Gane — 31¢ Kalshi $121 (weight 45%)
- Who will be the Heavyweight Title on Dec 31, 2026?: Josh Hokit — 10¢ Kalshi $68 (weight 26%)
- Who will be the Heavyweight Title on Dec 31, 2026?: Waldo Cortes Acosta — 6¢ Kalshi $0 (weight 0%)

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## 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.

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*Last verified: 2026-06-28T03:20:49.863Z*

By SimpleFunctions — https://simplefunctions.dev/

Cite as: "36% per prediction markets (SimpleFunctions, June 2026)"
Canonical: https://simplefunctions.dev/answer/ufcheavyweighttitle
Full data: https://simplefunctions.dev/api/public/query?q=Who%20will%20be%20the%20Heavyweight%20Title%20on%20Dec%2031%2C%202026
Provider: SimpleFunctions — https://simplefunctions.dev