Prices come from two prediction markets. Each is calculated on its own, and you can switch between them on the index.
A prediction market with public order books. The index reads its 2028 Democratic nominee, Republican nominee and presidential-winner markets.
A U.S. exchange regulated by the Commodity Futures Trading Commission. The index reads the same three 2028 markets from its public price feed.
Polymarket and Kalshi settle their contracts under different rules. Kalshi’s presidency market pays out on who is inaugurated; Polymarket’s on how major news outlets call the race. Averaging them would hide those differences, so each market’s numbers stay separate.
Betfair and traditional sportsbooks aren’t used. Their odds include a bookmaker margin that has to be removed first, and licensed access to their data hasn’t been set up.
A scheduled collector reads both markets every hour and saves a snapshot. The site shows the latest snapshot and the time each market was last observed. How updates work
This is an independent research project, not affiliated with either market. Market data remains subject to each provider’s terms of use.