Prediction markets just posted their biggest week yet, and Kalshi did most of the heavy lifting. Weekly contract volume reached $11.26 billion, according to DeFi Rate, with Kalshi accounting for 90.4% of that activity. Sports and combo markets were the main drivers, giving the exchange another huge week as trading continues to scale.
That kind of share is hard to ignore. You can debate which platform has the better product or broader market mix, but volume this concentrated creates a very real advantage. More activity usually means deeper markets, easier execution, and more reasons for traders to keep coming back.
Kalshi is Creating a Serious Liquidity Gap
The headline number is the record, but the market share might matter even more. If one platform is handling roughly nine out of every ten dollars in weekly contract volume, competitors have a much tougher job convincing active traders to move elsewhere. Liquidity tends to attract more liquidity, especially in markets where people care about fast execution and tighter pricing.
That puts pressure on platforms like Polymarket, Novig, and Robinhood's prediction market products. They can compete on unique contracts, user experience, or distribution, but matching Kalshi's depth is a different challenge. The biggest platforms are no longer just fighting for attention; they're fighting for the flow that makes the entire marketplace feel more usable.
A few numbers stand out from the latest report:
- Weekly prediction market volume reached $11.26 billion
- Kalshi captured 90.4% of that total
- Sports and combo contracts drove much of the growth
- Novig recently generated $125 million in its opening week
- Kalshi's own weekly activity remained far larger
Sports Keep Powering the Growth Story
Sports continue to sit at the center of Kalshi's expansion. Recent data showed sports as its largest 24-hour category by volume, with tennis, baseball and soccer markets appearing throughout the most active contracts. That helps explain why major sporting events and broader sports partnerships have become such an important part of the company's strategy.
The timing also works in Kalshi's favor. The US Open is underway, football season is approaching, and the platform has already shown how much activity a major global event can generate. Its World Cup markets produced at least $13.76 billion in tracked volume earlier this summer, setting an exchange record for a single event.
Huge Volume May Not Be Required for Good Forecasts
One interesting twist comes from Kalshi's own research. The company said an internal review covering 2.2 million data points found that markets could remain accurate a week before resolution with only around $50,000 to $60,000 in trading volume. That suggests reliable forecasts don't necessarily require billions of dollars flowing through a market.
That finding creates an interesting contrast with Kalshi's current scale advantage. Deep liquidity still matters for execution and the overall trading experience, but smaller markets may not need massive volume to produce useful probabilities. You could have a relatively quiet market that still does a good job reflecting available information.
The Trade Handle Prediction Markets Take
Kalshi's 90.4% share is the number we keep coming back to. Hitting an $11 billion week is impressive, but controlling nearly the entire market's trading activity creates a much bigger strategic advantage. Competitors now need to decide whether they can realistically challenge that liquidity or whether they're better off building around categories where Kalshi isn't as dominant.
The accuracy study makes that battle a little more interesting. Smaller platforms may not need to match Kalshi dollar for dollar to create useful markets, but they still need enough activity to make the product feel alive. For us, the next phase isn't just about who posts the biggest volume number; it's about whether anyone can turn a smaller slice of the market into a real competitive foothold.