83% — Will the margin of victory for Reform UK in the 2026 Clacton by-election be above 35% Leader: Reform UK, ≥10% at 83% · Kalshi 83% · 16 contracts · $181 volume · medium confidence Updated 2026-07-13 03:30:48 UTC Tracks the leading outcome in a winner-take-all prediction market set with 16 outcomes. Why this matters: This contract estimates a 71% probability that Reform UK will win the 2026 Clacton by-election by more than 35 percentage points. The market reflects strong confidence in Reform's dominance in the constituency, though there is material uncertainty about whether the victory margin will exceed 35% versus a smaller but still decisive margin. Key drivers include Reform's current polling strength in Clacton, the fragmentation of opposition votes, and local candidate factors. The resolution depends on actual vote tallies when the by-election occurs; margins could narrow if opposition parties coordinate or if turnout patterns differ from expectations. The price gradient across the contract tier suggests traders see roughly 25-30 point margins as plausible, with outcomes above 35 points considered likely but not certain. Key factors: - Current polling and historical voting patterns in Clacton relative to Reform's national performance - Degree of tactical voting coordination or vote-splitting among Labour, Conservative, and Liberal Democrat voters - Local candidate quality, campaign intensity, and ground organization efforts by all competing parties - Voter turnout rate and demographic composition of the by-election electorate compared to recent general elections - Timing of the by-election and whether it occurs during periods of higher or lower national political salience Contracts: - Will the margin of victory for Reform UK in the 2026 Clacton by-election be above 10%?: Reform UK, ≥10% — 83¢ Kalshi $143 (weight 79%) - Will the margin of victory for Reform UK in the 2026 Clacton by-election be above 5%?: Reform UK, ≥5% — 83¢ Kalshi $33 (weight 18%) - Will the margin of victory for Reform UK in the 2026 Clacton by-election be above 15%?: Reform UK, ≥15% — 78¢ Kalshi $0 (weight 0%) - Will the margin of victory for Reform UK in the 2026 Clacton by-election be above 20%?: Reform UK, ≥20% — 74¢ Kalshi $0 (weight 0%) - Will the margin of victory for Reform UK in the 2026 Clacton by-election be above 25%?: Reform UK, ≥25% — 72¢ Kalshi $0 (weight 0%) - Will the margin of victory for Reform UK in the 2026 Clacton by-election be above 30%?: Reform UK, ≥30% — 70¢ Kalshi $0 (weight 0%) - Will the margin of victory for Reform UK in the 2026 Clacton by-election be above 35%?: Reform UK, ≥35% — 68¢ Kalshi $0 (weight 0%) - Will the margin of victory for Reform UK in the 2026 Clacton by-election be above 40%?: Reform UK, ≥40% — 62¢ Kalshi $0 (weight 0%) - ... and 8 more --- ## 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: 2026-07-13T03:20:52.482Z* By SimpleFunctions — https://simplefunctions.dev/ Cite as: "83% per prediction markets (SimpleFunctions, July 2026)" Canonical: https://simplefunctions.dev/answer/clactonbymov Full data: https://simplefunctions.dev/api/public/query?q=Will%20the%20margin%20of%20victory%20for%20Reform%20UK%20in%20the%202026%20Clacton%20by-election%20be%20above%2035%25 Provider: SimpleFunctions — https://simplefunctions.dev