Executable ask

Also called best ask · offer

The price you can actually buy at right now — the best resting offer for the exact contract you want, not the last price printed.

Every lock computed on this site is priced off the ask of the exact contract being bought, never off the last trade and never off the midpoint. The reason is not fussiness. A lock claimed on last-trade prices is fiction: a longshot whose last print was a penny can be offered at two cents, which doubles the true cost of that leg and turns a displayed edge into a loss.

Per venue, the executable buy price is: on Polymarket, the best ask for YES, and one minus the best bid for NO — because buying NO at q crosses the same book as selling YES at 1 − q. On Kalshi, both asks are served directly, and the NO ask equals one minus the YES bid, which was verified against the live book rather than assumed.

The discipline extends to absence. When either ask of a direction is missing or degenerate — not strictly between zero and one — the splitter returns not viable and the interface is required to say there is no live book, rather than fabricate a lock from a price nobody is offering. A tool that shows you an arbitrage you cannot execute is worse than one that shows you nothing.

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Definitions describe how Polymarket and Kalshi behave and how WhaleTracks models them; venue rules and fee schedules can change, so confirm anything you size a position on with the venue itself. WhaleTracks is informational analytics, not financial advice. Past performance does not guarantee future results.