79% — Who will be the Lightweight Title Holder on Dec 31, 2026
Leader: Justin Gaethje at 79% · Kalshi 79% · 6 contracts · $8K volume · medium confidence
Updated 2026-07-13 06:45:08 UTC

Tracks the leading outcome in a winner-take-all prediction market set with 6 outcomes.

Why this matters:
This market estimates a 56% probability that one specific fighter will hold the UFC Lightweight title on December 31, 2026. The current leader, ITOP, has nearly 3.5x the probability of the runner-up at 16%, suggesting market confidence in a particular outcome. The lightweight division's title trajectory depends primarily on whether the current champion retains the belt through 2026 or loses it to a challenger. Major factors include scheduled title fights, injury status of top contenders, and the competitive ranking within the division. The market will face substantial resolution clarity at each title defense or change of hands occurring between now and year-end. Kalshi's three linked contracts indicate traders are pricing the full range of potential lightweight title holders rather than treating this as binary.

Key factors:
- Current lightweight champion's injury status and fight schedule through December 2026
- Number and quality of ranked challengers who could feasibly capture the title before year-end
- Timing of scheduled lightweight title defenses or championship bouts on the UFC calendar
- Historical retention rate for UFC lightweight champions over 8-month periods
- Market's pricing of the runner-up candidate (16%) versus ITOP leader (56%) implies specific fighter assumptions that can be validated against announced matchups

Contracts:
- Who will be the Lightweight Title Holder on Dec 31, 2026?: Justin Gaethje — 79¢ Kalshi $2K (weight 20%)
- Who will be the Lightweight Title Holder on Dec 31, 2026?: Ilia Topuria — 12¢ Kalshi $241 (weight 3%)
- Who will be the Lightweight Title Holder on Dec 31, 2026?: Arman Tsarukyan — 10¢ Kalshi $2K (weight 19%)
- Who will be the Lightweight Title Holder on Dec 31, 2026?: Paddy Pimblett — 5¢ Kalshi $2K (weight 25%)
- Who will be the Lightweight Title Holder on Dec 31, 2026?: Islam Makhachev — 5¢ Kalshi $2K (weight 21%)
- Who will be the Lightweight Title Holder on Dec 31, 2026?: Charles Oliveira — 3¢ Kalshi $936 (weight 12%)

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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: 2026-07-13T06:20:49.874Z*

By SimpleFunctions — https://simplefunctions.dev/

Cite as: "79% per prediction markets (SimpleFunctions, July 2026)"
Canonical: https://simplefunctions.dev/answer/ufclightweighttitle
Full data: https://simplefunctions.dev/api/public/query?q=Who%20will%20be%20the%20Lightweight%20Title%20Holder%20on%20Dec%2031%2C%202026
Provider: SimpleFunctions — https://simplefunctions.dev