Prediction market platform Kalshi continues its steady expansion across brokerage platforms, with Webull becoming the latest to offer Kalshi markets to its users. While great for liquidity, the expansion comes with costs for traders in the form of increased fees like those Kalshi recently announced on sports-related contracts now being offered at Robinhood.
Webull's front page this morning is sleek!
— Tarek Mansour (@mansourtarek_) April 21, 2025
You can now trade some Kalshi prediction markets on Webull, starting with indices.
More markets coming soon... pic.twitter.com/X0BnGoOJgi
The move comes just weeks after Robinhood, one of the most popular retail trading apps, rolled out a selection of Kalshi prediction markets to its 25 million users. Robinhood’s initial launch of its “prediction markets hub” included markets for March Madness and the target federal funds rates, and the company has begun to roll out more markets tied to major economic indicators and sports events.
In total, seven markets available on Robinhood are tied to major economic indicators—Fed decision, inflation, CPI, Jobs numbers, GDP growth, and Gas prices—while the other 22 include controversial sports event contracts for the current NBA and NHL playoffs. Robinhood also had a Masters market that, combined with Kalshi, helped facilitate $86.8 million in trades.
Meanwhile, Webull’s partnership with Kalshi is a soft launch that includes only markets on hourly index prices for the S&P 500 and NASDAQ.
What’s next for Kalshi’s brokerage partnerships?
Kalshi’s presence on platforms like Robinhood and Webull signals a broader strategy: to normalize prediction markets alongside traditional stocks and ETFs, while gaining access to large existing customer bases with proven appetites for trading.
Robinhood has leaned into sports and economic markets but steered clear of Kalshi’s growing pop culture markets, which cover music, television, movies, and video games.
“We would like to get more culture markets on robinhood- but ultimately, it is their decision with timing,” a member of Kalshi’s markets team posted in the company’s community Discord. “However, we are heading in the right direction, with them putting more of our markets on there, so stay tuned.”
One of Kalshi’s fastest-growing markets lets users predict Rotten Tomatoes scores for upcoming movie releases.
Trading volumes for these movie markets have skyrocketed over the past year: a good showing used to mean about $200,000 in volume, but today, movies routinely eclipse $1 million. This year, $2.4 million was traded on Captain America: Brave New World’s Rotten Tomatoes score in February, followed by another $2.1 million in March on Mickey 17’s.
A top trader known as ‘zubbybadger’—currently ranked No. 7 on Kalshi’s all-time leaderboard with $1.1 million in profit as of April 2025—has earned a whopping $234,000 trading Rotten Tomatoes predictions.
If and when Robinhood moves into pop culture events, don’t be surprised if it starts with Kalshi’s already-proven Rotten Tomatoes markets, which are likely to catch on quickly with Robinhood users.
“There’s nothing I want more than to put rotten tomatoes markets on robinhood,” said the same Kalshi employee.
Buyer beware: Fees matter
Kalshi’s expansion has come at a small but not insignificant price to traders.
In an email sent Saturday, Kalshi said it would raise fees on eight sports-related event series connected to its Robinhood rollout.
Market makers (limit orders) now face $0.0025 fees per contract across Kalshi’s NBA and NHL markets, mirroring earlier fee increases for Kalshi’s economic markets that also launched on Robinhood. Before the partnership, only takers (quick orders) were subject to fees.
“You can expect to see many more traders in these markets than you usually would!” the email said. “These fees are currently necessary to ensure we can offer these markets on brokerages.”
Kalshi’s trading fees, at just 0.25% per contract, have little effect on smaller traders and stay manageable for mid-size players and market makers.
But it’s a different story on Robinhood, where traders pay a hefty 2¢ per contract, no matter the side. The result? Profits are harder to come by, and market accuracy suffers, especially in a sport like golf where a 2¢ fee quickly cuts the implied probability of a 1¢ longshot from 99-to-1 to 33-to-1.
The rollout of Kalshi’s markets to mainstream brokerage platforms is undoubtedly a milestone for prediction market proponents, but users should be aware of each platform’s fee structures. Unlike traditional stock trading, where zero-commission models have become the norm, trading events involve notable fees that don’t appear to be going away anytime soon.
As prediction markets become more accessible, understanding the true cost of trading will be just as important as picking the right side of a contract.
