Why prediction-market prices differ between venues

A similar title may hide a different contract

Different deadlines, resolution sources or cancellation rules can make two contracts respond to different facts. Match those conditions before interpreting a price difference.

Compare the same kind of quote

A last price from one venue and an ask from another do not describe the same opportunity. Compare the same side and order size at a stated time, including fees and available depth.

An older quote may reflect information that was current when it was observed. Retaining its timestamp makes that limitation visible; retrying a failed fetch must not make the quote appear fresh.

A difference is a research question

Document which venues were checked, the exact contracts, the observation window and the missing inputs. A discrepancy does not by itself prove a mistake or guarantee an executable opportunity.

A rule difference can explain a price difference

Imagine two contracts about a monthly statistic. One resolves on the first published estimate; the other uses a revised figure released later. Even if their short titles look alike, a revision could change one result without changing the other. The price difference would concern different claims.

The same problem appears when one question uses a strict threshold and another includes equality, or when one source measures a value at a particular instant and another uses an average. Record the distinction before calling either price inconsistent.

The displayed price is not the complete comparison

For matched contracts, identify the order size the quote supports and the costs attached to that order. A price available for a small quantity does not establish the cost of a larger position. A fee can also depend on the market or transaction type.

Our comparison pages keep product-specific fee descriptions attached to their sources. They do not convert missing depth, spread or charges into a universal cheapest-platform ranking.

Build a comparison another reader can reproduce

Save the two stable contract identifiers, the exact outcomes, the observation times and the quote types. Link the rules that establish equivalence. List any material unknowns separately from the observed difference.

When the evidence stops at a shared headline, describe the contracts as related. When timing or costs are incomplete, keep that limitation beside the figure. An unexplained difference is a reason for further research.

Sources and citation

1. Kalshi: market FAQs and settlement
2. Polymarket international: resolution
3. Kalshi: fees
4. Polymarket international: fees

PlayPicks analysis is original synthesis. Linked provider documents remain the primary source for their own contract terms.