How does All Top pick the best price?
The highlighted best price on a market page is the highest yes odds among the venues we cover.
Please note: the best price is not a recommendation and excludes fees. It is up to you to determine if it is the best side of the trade.
How to read the price table
The per-venue table under each market is the full picture the highlight summarizes. Don't stop at the highlight:
Know your side. The highlight marks the venue rating the outcome most likely. If you're buying yes, a lower price is a better entry; the highlighted venue is the strongest price only if you're on the no side or reading the odds as a forecast.
Count the venues. A best price among three listings means more than a best price that's the only listing.
Check the spread. Convergence suggests a settled consensus; divergence suggests movement or thin liquidity.
Check the fees. The best price isn't the best deal until fees say so.
The price history chart on the same page shows how the market got here, and how news stories link to markets explains where the related headlines come from.
The selection rule
Each market on AllTop carries prices from every venue we ingest that lists it. The backend ingests each venue's API feed, cleans the data, and sorts it by venue, with the most liquid venues first. The displayed best yes price is then determined in two steps.
First, if the backend has computed an explicit best-yes value for the market, we use it, matched to the venue whose price equals that value within a hundredth of a point.
Otherwise, the best price is the highest yes odds across the listed venues.
When two venues show identical prices, the tie goes to whichever venue sorts first. In practice, this is either Kalshi or Polymarket, since the sort favors liquidity. Nothing editorial breaks the tie.
The venue spread
Alongside the best price, our market pages show the spread between venues. This is the backend's computed spread (where available), otherwise the highest yes price minus the lowest across venues.
When only one venue prices the market, the spread is zero.
The venus spread is a gap between venues, not a bid–ask spread within one order book.
A wide spread can mean the market is reacting to news and the venues haven't converged, that liquidity is thin on one of them, or occasionally a genuine arbitrage opportunity. Our Terminal's arbitrage scanner (what an account unlocks) provides easy access to arbitrage detection.
The venues' contracts can also carry different resolution criteria for what looks like the same event, so read the resolution terms before treating a gap as mispricing.
What the best price does not include
Trading fees are NOT factored into the best-price selection or the spread.
Each venue has a different fee schedule and a venue showing the nominally best price can deliver a worse net payout after fees than a competitor a tick behind it.
Each venue's fee information appears as separate disclosure on the page. Before acting on the highlighted price, check the fee line for the venues involved, because "best price" on AllTop means best listed price, not best price net of costs.
The comparison is also only as wide as our data coverage.
AllTop ingests live prices from Kalshi, Polymarket, and Polymarket US. Platforms outside that set may list the same event at different prices; they appear on AllTop in editorial coverage but not in the live comparison table.
See how the aggregation works for the full picture of what's ingested.
If a venue's price looks off, check the data status label and timestamp on the page first — what the LIVE label means explains how to read them.
Related:
The highlighted best price on a market page is the highest yes odds among the venues we cover. It isn't a recommendation, it excludes fees, and depending on your side of the trade it may not be your best entry.
How to read the price table
The per-venue table under each market is the full picture the highlight summarizes. Don't stop at the highlight:
Know your side. The highlight marks the venue rating the outcome most likely. If you're buying yes, a lower price is a better entry; the highlighted venue is the strongest price only if you're on the no side or reading the odds as a forecast.
Count the venues. A best price among three listings means more than a best price that's the only listing.
Check the spread. Convergence suggests a settled consensus; divergence suggests movement or thin liquidity.
Check the fees. The best price isn't the best deal until fees say so.
The price history chart on the same page shows how the market got here, and how news stories link to markets explains where the related headlines come from.
The selection rule
Each market on AllTop carries prices from every venue we ingest that lists it. The backend ingests each venue's API feed, cleans the data, and sorts it by venue, with the most liquid venues first. The displayed best yes price is then determined in two steps. First, if the backend has computed an explicit best-yes value for the market, we use it, matched to the venue whose price equals that value within a hundredth of a point. Otherwise, the best price is the highest yes odds across the listed venues.
When two venues show identical prices, the tie goes to whichever venue sorts first — in practice Kalshi or Polymarket, since the sort favors liquidity. Nothing editorial breaks the tie.
The venue spread
Alongside the best price, market pages show the spread between venues: the backend's computed spread where available, otherwise the highest yes price minus the lowest across venues. When only one venue prices the market, the spread is zero. This is a gap between venues, not a bid–ask spread within one order book.
A wide spread can mean the market is reacting to news and the venues haven't converged, that liquidity is thin on one of them, or occasionally a genuine arbitrage opportunity, which signed-in users can check with the Terminal's arbitrage scanner (what an account unlocks). The venues' contracts can also carry different resolution criteria for what looks like the same event, so read the resolution terms before treating a gap as mispricing.
What the best price does not include
Trading fees are not factored into the best-price selection or the spread. Venues charge different fees, and a venue showing the nominally best price can deliver a worse net payout after fees than a competitor a tick behind it. Each venue's fee information appears as separate disclosure on the page. Before acting on the highlighted price, check the fee line for the venues involved, because "best price" on AllTop means best listed price, not best price net of costs.
The comparison is also only as wide as our data coverage. AllTop ingests live prices from Kalshi, Polymarket, and Polymarket US. Platforms outside that set may list the same event at different prices; they appear on AllTop in editorial coverage but not in the live comparison table. See how the aggregation works for the full picture of what's ingested.