any sufficiently advanced technology is indistinguishable from magic. senior software engineer @coinbase
New York, NY
Joined December 2019
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0/ i analyzed every single trade on kalshi from 2021 to 2025.
i found a systematic wealth transfer where "takers" pay a massive premium for affirmative outcomes, and "makers" harvest the edge without needing to predict the future.
here is the data
formalized
papers.ssrn.com/sol3/papers.…
The Microstructure of Wealth Transfer in Prediction Markets
papers.ssrn.com/sol3/papers.…
We analyze 72.1 million transactions executed on Kalshi, a CFTC-regulated prediction market, from June 2021 through November 2025. Aggregate prices are well calibrated, but calibration conceals a persistent internal transfer. Because YES and NO positions at the same cost basis risk identical capital for identical payoffs, neither risk preferences nor misperception of the probability level can price them differently; in the data, YES contracts underperform NO contracts of equivalent cost basis by up to 64 percentage points, concentrated at longshot prices. Demand responds to the affirmative framing of the event itself; we term the premium this flow pays the optimism tax. Decomposing returns by order-book role identifies who collects it: liquidity takers earn mean excess returns of -1.12% per trade while makers earn +1.12%, and maker returns are statistically and economically indistinguishable across position directions, indicating accommodation of biased flow rather than superior forecasting. An exact decomposition of taker losses attributes roughly three-quarters of the transfer to execution within price-direction cells and the balance to the accommodation of directionally tilted flow; selection across price levels, the longshot bias proper, contributes essentially nothing. The transfer ranges from 0.17 percentage points in financial contracts to more than 7 in media and geopolitical categories, and it emerged only after post-election volume growth attracted professional liquidity providers: the maker-taker gap reversed by 5.3 percentage points. The forecasting accuracy of prediction markets derives not from the rationality of individual participants but from a microstructure in which liquidity provision monetizes behaviorally biased order flow.
xitter.cf/beckerrjon/status/2021…
updated & live data available soon.
added polymarket data to the public dataset.
400m+ trades going back to 2020.
36gb compressed.
MIT licensed, free to download via @Cloudflare R2.
> what can i do with this data?
make sick visualizations, perform deep data analysis, contribute to prediction market research, ...
added polymarket data to the public dataset.
400m+ trades going back to 2020.
36gb compressed.
MIT licensed, free to download via @Cloudflare R2.
added polymarket data to the public dataset.
400m+ trades going back to 2020.
36gb compressed.
MIT licensed, free to download via @Cloudflare R2.
prediction markets are remarkably accurate
Prediction markets are the ultimate form of truth seeking. When there’s skin in the game, the output is far more reliable. Everything else is biased by someone's agenda. I think we’ll look back at prediction markets as a breakthrough in how we discover truth in the world.
Prediction markets are now fully live in the U.S. on Coinbase, you can trade what’s happening in sports, politics, culture, news, and more.
Update your app and look for the "Predict" tab at the bottom.
started collecting all polymarket data as well for a comparative accuracy analysis
no hard eta, data will first be available here:
github.com/Jon-Becker/predic…
2/ if interested in the dataset, you can find it here
github.com/jon-becker/predic…
