The Overround / AI models
Which lab has the best model is worth $15.5m in traded volume on Polymarket, across 44 live markets. On Kalshi, the regulated American exchange, the number of markets on whether a model is any good is zero.
Kalshi runs plenty with "AI" in the title. Every one of them is about the business: when OpenAI files, which bank leads the book, what sector Anthropic gets assigned to, who wins which lawsuit. Useful if you trade equities. Useless if what you actually want to know is whose model is ahead this month.
That is not an impression. We swept all 2,800 open Kalshi events. Eighteen mention AI anywhere in the title. Not one of them prices a model.
Polymarket runs that market, it is deep, and almost nobody publishes what it costs to trade.
Which company has the best AI model end of September?
Backing every outcome on this market costs 102%. A fair book is 100. The extra 2 points is the house's.
See this on PolymarketRanked by volume. The book is what it costs to back every outcome: a fair one sums to 100%, and the excess is the house's cut. It is only shown where the whole field is quoting, because a partial sum is not a book.
The dearest AI market on the board is “Gemini 4.0 released by...?” at 171%. On a market with $28k of liquidity sitting in it, that is a 71 point toll on having an opinion about which lab wins.
Live, updates itself, free, no tracking, no account. If you write about model releases and want the current odds sitting in the post, paste this:
<iframe src="https://theoverround.com/embed/ai" width="100%" height="260" style="border:1px solid #26262E;border-radius:12px" loading="lazy" title="AI model odds, via The Overround"></iframe>
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Every other page on this site is anchored to Kalshi. The scanner walks Kalshi's events and the market pages are keyed on Kalshi tickers, which works fine until the most interesting category on the internet turns out to exist only on the other venue. This page is built straight from Polymarket, so it sees what the rest of the site structurally cannot.
There is no cross-venue comparison here for the obvious reason: there is nothing to compare it to. That is the finding rather than a gap in the reporting.
Prices are raw asks read from Polymarket within the last hour, which is what it costs to take the position rather than a midpoint nobody trades at. Some links on this page earn us a commission, which never affects what is listed or in what order: see the disclosure page. Ranking here is by volume, and volume is not for sale.