MLB Cross-Venue Matched Book (Polymarket × Kalshi) — Sample

Polymarket and Kalshi prices for the same MLB game, aligned tick-for-tick on one timeline, with the eventual winner labeled on every row. One settled game (Arizona Diamondbacks @ Minnesota Twins, 2026-06-21); the two venues tracked each other to under one cent through the Twins' comeback win. Neither venue sells its historical order book and it cannot be reconstructed after the fact. Polymarket runs one outcome per binary market (the other side is the exact complement, 1 − poly_mid); prices are book midpoints; ~30–60s granularity; settlement is Kalshi's finalized resolution. See README/SCHEMA for the full reference. The complete multi-day archive and more prediction-market datasets are at zenhodl.net/products.