Will Labour win the next UK general election?
Polymarket vs Kalshi spread: 6.0%. Buy YES on Polymarket at 68¢, sell YES on Kalshi at 74¢. Data via Musashi — last updated hourly.
Last updated: Apr 29, 2026, 12:00 AM UTC
Current Spread Data
How This Arbitrage Works
Both Polymarket and Kalshi are pricing the same event but at different probabilities. This 6.0% gap lets you trade both sides simultaneously:
Frequently Asked Questions
What is the current arbitrage spread for "Will Labour win the next UK general election?"?
The current gross spread is 6.0 percentage points: Polymarket prices YES at 68¢ and Kalshi prices YES at 74¢. This data updates hourly via Musashi.
How do I trade this arbitrage?
Buy YES on Polymarket at 68¢ per share. Simultaneously sell YES on Kalshi at 74¢. Your locked-in gross spread is 6.0¢ per share because you collect the higher sale price and pay the lower entry price up front. If YES resolves, the long pays $1 and the short owes $1; if NO resolves, both legs expire worthless, and in either case you keep the initial spread before fees and slippage.
Is this arbitrage risk-free?
Near risk-free in theory, but execution risk exists. Both legs must fill before the spread closes. Slippage, position limits, and the time required to withdraw funds between platforms reduce the realized profit. Model your net spread after fees and slippage before committing.
How often does this spread update?
Musashi polls Polymarket and Kalshi every 15-20 seconds and this page revalidates every hour. For real-time spread data, use the Musashi arbitrage API: GET /api/markets/arbitrage.