Polymarket and Kalshi Diverge Due to Definitional Differences, US Government Shutdown Gamble Highlights Prediction Market 'Definition Precision' Issues

Odaily News As the US Congress failed to complete all legislative procedures for the appropriations bill, the US government is expected to enter a short-term, partial shutdown starting Saturday, Eastern Time. However, this event also highlights the issue of contract "definition precision" in prediction markets. Prediction contracts regarding "whether the government will shut down" on Polymarket and Kalshi have diverged due to different trigger condition definitions. Related contracts on Polymarket show a government shutdown probability of approximately 88%, while a similar contract on Kalshi shows a probability as high as about 93%. The reason may be that some contracts use whether the US Office of Personnel Management (OPM) officially announces a shutdown as the settlement basis, considering it valid even if it's only a partial shutdown. This event underscores that in political and macroeconomic events, prediction markets are highly sensitive to contract trigger conditions, the official confirming entity, and timing nodes. The contract details themselves have become a significant factor influencing the odds. (CoinDesk)