Cross-Platform Arbitrage Playbook: Kalshi & Polymarket Execution
The Lock
Buy the YES on the cheap venue and the NO on the other so combined cost < 1.00. At settlement exactly one pays 1.00.
Execution Checklist
- Confirm the economic events are identical (same close date, same resolution source).
- Size equal notional on both sides.
- Account for fees, withdrawal floats, and settlement lag.
- Take the edge only when diff ≥ 2–3¢ after costs.
Common Mistakes
- Mismatched events (different expiry or resolution rule).
- Ignoring that Polymarket requires USDC and may be restricted.
- Over-sizing before confirming the fill on both sides.
FAQ
Is it really risk-free? Settlement/event risk remains; the price lock removes directional risk only.
