The Same Bet on Two Venues: Backtesting the HIP-4 ↔ Polymarket Basis
The July 2026 Fed decision traded at the same time on HyperLiquid's HIP-4 and on Polymarket. Two order books, one outcome — so the price gap between them is a backtestable arbitrage. Working entirely from on-chain fills, we measure that basis over ~36 hours (>2¢ wide a quarter of the time), then dissect the resolution to the second: both venues priced the hold within ~8s, HIP-4's thin book lagged ~90s, and — the part everyone gets wrong — the real money was a directional pre-bet (~$38k), not the post-news snipe (~$7k).