A quick survey of prediction market fees
not so simple
Disclosure: I run Kalshinomics.com, which may earn Kalshi referral fees. I may trade event contracts on Kalshi and securities on other platforms. Readers should consider this relationship when evaluating my analysis. For educational purposes only, not investment advice.
Monetizing an exchange is complex. Forget Goodnight Moon and tuck your children in to the calming rhythm of 31 pages of fee details for NYSE. Fee structures matter now more than ever. With prediction markets attracting serious capital, the decisions exchanges make about fees and distribution deals will shape both their bottom lines and how users experience their platforms.
In a previous article I discussed Kalshi’s unique fee structure, let’s compare to a few other venues:
Kalshi has a list of which markets have a maker fee, see below for ref links1
The multi-billion-dollar gorilla is Polymarket, which has yet to flip the switch on fees. Of the exchanges that charge fees, I like Kalshi’s fee structure best as it distorts the tail probabilities the least. I also predict the overall level of fees will go down over time. Kalshi is already experimenting with volume and liquidity rebates in some markets.
For a further breakdown of ForecastEx’s structure Adhi at “50 Cent Dollars” has already done a good writeup on it.
One interesting quirk is Robinhood, which allows you to trade on Kalshi (and less interestingly ForecastEx) through the Robinhood mobile app (though not on desktop).
Instead of using Kalshi’s fee structure, Robinhood charges a $0.01 fee plus Kalshi gets a flat $0.01 on trades through the platform. This creates an odd structure where the same trade can have drastically different fees depending on the source of the order. This also prevents any trades on contracts priced at 98% or 99% (Robinhood simply won’t execute the trades)
The experience is not as complete as what’s available via the Kalshi app, it appears the only order type is an Immediate-or-cancel limit order with price set to the best offer. On Kalshi’s platform you get paid interest on your total balance including outstanding positions, I was unable to find whether you get interest on trades on Kalshi via the Robinhood app. Robinhood has created a simplified experience that may be easier to navigate for new users but more advanced traders will get a better fee structure and greater flexibility in order management directly on Kalshi. It has clearly been very successful for both partners, with over $2 billion trading in Q3 2025.
Here’s the fees on the same trade whether traded direct on Kalshi or via Robinhood→Kalshi:
Similar to Robinhood→Kalshi, Crypto.com uses mostly fixed fees but has an unusual fee on winners that varies with contract value:
For contract values of $10 and $100, there is additional fee on winning trades that’s $0.1 (1%) for $10 contracts, and $1.99 (~2%) for $100 contracts. This is bizarre! Most of the time fees go down as a % of total size when notional goes up. Not sure what the reasoning was here.
What’s Next
With Draftkings acquiring Railbird I am intrigued to follow how they’ll structure and which markets they’ll list. At the time of writing Railbird has a link on their homepage to a “Fee Structure” tab that redirects to a “Coming Soon” placeholder.
As soon as Polymarket launches in the US pay close attention any news or updates to their fee structure.
Disclaimer
The information provided in this blog is for informational and educational purposes only and should not be construed as investment, financial, legal, or tax advice. Opinions expressed are solely those of the author.
The author may hold positions—long or short—in securities, contracts, or markets mentioned, and these holdings may change at any time without notice.