Kalshi Sees 1,520% Traffic Surge as Supreme Court Weighs Sports Betting Legality

Kalshi’s numbers are staggering. The prediction market platform pulled in 15.4 million US visits in July, up from under 1 million in August 2025 — a 1,520% jump in roughly a year. And the legal heat is rising just as fast as the traffic.

Trading volume tells an even wilder story. Kalshi recorded around $40 billion in monthly notional trading volume in August, compared to $874 million a year earlier. That’s a 4,500% increase, per Dune Analytics data. To put it bluntly: Kalshi basically dominated the prediction market space, accounting for almost 79% of the sector’s total volume, which hit $50.7 billion in the same period. Those are numbers that would make most fintech founders dizzy.

Sports contracts are the engine here.

They made up 83% of Kalshi’s trading volume in July. That concentration is either a strength or a vulnerability — probably both — depending on how courts rule. New Jersey has taken the question all the way to the US Supreme Court, asking whether Kalshi’s sports contracts fall under federal oversight or state gambling laws. No ruling yet. No timeline given publicly. Kalshi didn’t comment on the legal proceedings, and the company hasn’t addressed questions about traffic from restricted jurisdictions either.

Sports Contracts Drive Volume — and Risk

The reliance on sports contracts is hard to overstate. When 83% of your trading volume sits in one contract category that’s actively being litigated, the regulatory outcome isn’t just a legal footnote — it’s an existential question for the business model. If the Supreme Court sides with New Jersey and pushes these contracts into state gambling law territory, Kalshi’s core revenue driver faces a very different operating environment. If federal oversight wins out, the platform likely keeps its current structure. Unclear which way it goes.

What’s clear is that Kalshi’s domestic focus has intensified. US traffic made up roughly 72.8% of visits in August 2025. By July, that share had climbed to nearly 80%. The platform is more American than ever, which makes Washington’s and state-level decisions more consequential than ever.

Canada and UK Traffic Climbs, But Share Shrinks

International interest is real, but it’s kind of getting swamped by US growth. Canada sent about 450,000 visits in July, up from 50,000 the previous August. The UK jumped from 31,000 to 296,000. Big percentage gains on their own. But as shares of total traffic, Canada dropped to 2.3% and the UK to 1.5%. The US surge is just that dominant.

Related: Kalshi Halts Betting on Its Supreme Court Fate Amid $500K Fine Threat from Michigan

Both Canada and the UK have restrictions that block direct trading on Kalshi’s platform. So the visits aren’t necessarily translating to accounts in the same way US traffic does. That gap between interest and access is a real problem — and Kalshi’s answer in Canada, at least, is a partnership.

In June, Kalshi teamed up with Wealthsimple to offer Canadian users access to its contracts through a new app. It’s a workaround, basically. Canadian users can’t trade directly on Kalshi, but through a local financial services company they can get in. It’s a smart move, and probably the template for how Kalshi thinks about restricted markets going forward. No similar arrangement has been announced for the UK.

The Wealthsimple deal is worth watching. Wealthsimple has a large, digitally native Canadian user base — the kind of retail investor that’s already comfortable with app-based investing and probably curious about prediction markets. Whether that translates into meaningful volume from Canada remains to be seen. No numbers have been shared yet on how the partnership is performing.

What the Growth Actually Means

Fifteen million visits a month is not a niche platform anymore. Kalshi has crossed into mainstream attention territory, at least by web traffic standards. Whether that translates into sustained trading volume depends on factors the company can’t fully control — court decisions, state-level regulatory moves, and whether sports betting adjacent products stay legal in their current form.

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The $40 billion monthly notional figure sounds enormous, but notional volume in prediction markets can be inflated by contract structure. Still, the trajectory from $874 million to $40 billion in one year is the kind of growth that attracts both investors and regulators.

And regulators are clearly paying attention. New Jersey going to the Supreme Court isn’t a small move. It’s a signal that at least one state sees Kalshi’s sports contracts as something that needs to be brought under state authority. Other states could follow with similar challenges.

Kalshi’s sports contracts accounted for 83% of July trading volume.