SimpleFunctions
4 source contracts·Kalshi 4·refreshed just now·Closes Dec 31, 2026 · 101d

Who will be the Heavyweight Title on Dec 31, 2026

Liquidity-weighted aggregate sits at 22% across 4 Kalshi contracts.

Implied probability

22%
0%50%100%

Kalshi

22%

4 contracts

Polymarket

not bound

Cross-venue gap

single venue

24h move

no pin

24h volume

$9K

4 contracts

Closes

Dec 31, 2026

101 days

30-day trend

0%50%100%-30d-3w-2w-1wtodayAggregate: 22% (20 days, 20 points)Aggregate: 22% on 2026-09-19
Aggregate of 4 contracts · 20d

Bracket families

2 clusters across 4 contracts.

These contracts were grouped by title similarity. The headline aggregate combines all clusters; verify the cluster you actually need before quoting a number.

Analysis

This probability estimates the likelihood that Tom Aspinall will hold the UFC Heavyweight Championship on December 31, 2026. At 66%, markets view Aspinall as the clear favorite to retain or regain the title by year-end, though Ciryl Gane (25%) represents a meaningful alternative outcome. The pricing reflects Aspinall's current standing in the heavyweight division and the historical difficulty of dethroning a champion within a specific timeframe. Between now and year-end, scheduled title fights, injury announcements, or unexpected upset results would be the primary drivers of probability shifts. Any title defense Aspinall loses or major fighter injury would significantly alter these odds. The resolution depends entirely on who officially holds the belt on the final day of 2026, making upcoming scheduled championship bouts the critical catalyst for clarity.

  • Tom Aspinall's current championship status and scheduled title defense dates between September 2026 and December 31, 2026
  • Ciryl Gane's ranking, recent performance record, and likelihood of earning a title shot within the specified timeframe
  • Josh Hokit's and other contenders' positions in the rankings and probability of ascending to a title fight
  • Injury risk to Aspinall or other top contenders that could alter the championship landscape
  • Historical turnover rates in the UFC Heavyweight division and average time between title changes

What moved the line

  • Sep 17Ciryl Gane38pp2664¢ · Kalshi
  • Sep 17Josh Hokit8pp614¢ · Kalshi
  • Sep 19Ciryl Gane6pp6559¢ · Kalshi
  • Sep 17Alex Pereira6pp28¢ · Kalshi

Recently closed in general

These markets stopped trading. Last odds and any captured outcome are shown above — full settlement detail lives at the venue.

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How we compute these odds

SimpleFunctions aggregates live prediction-market contracts from Kalshi and Polymarket. Each slug groups contracts that resolve on the same underlying event, identified by venue event_id.

For binary slugs, the headline probability is the liquidity-weighted mid-price across all bound contracts. For multi-outcome slugs (e.g. elections with 3+ candidates), the headline is the leader’s price; we never arithmetically average disjoint outcomes — that would produce a number with no real-world meaning.

Snapshots refresh every 5 minutes during market hours; daily aggregates are computed at 04:00 UTC. The 30-day sparkline is drawn from per-ticker daily means stored in market_indicator_daily; 24h delta and movement events are derived from the same source.

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