A prediction market looks simple from the cheap seats: pick an outcome, trade a contract, watch the odds move. Under the hood, it is a marketplace with all the usual physics, liquidity, incentives, fees, and the awkward question of who pays for growth. PitchBook’s new comparison of Kalshi and Polymarket is useful because it treats the category less like a political novelty and more like a business model stress test.
PitchBook's scorecard is really a marketplace scorecard
PitchBook says it now estimates Kalshi at $42.3 billion and Polymarket at $20.6 billion, citing stronger trading activity and a better revenue outlook. The more revealing line is operational: PitchBook says “Kalshi leads in trading volume,” while Polymarket’s U.S. platform has passed its international business as domestic adoption accelerates. That is not just a scoreboard. In marketplace terms, volume is inventory, customer proof, pricing signal, and retention loop packed into one metric.
The interesting part is that PitchBook frames the race around conversion mechanics, not just headline scale. Its analyst note compares how Kalshi and Polymarket turn trading activity into revenue, attract customers, and fund growth. That is the right lens, because prediction markets have the same cold start problem as every marketplace: nobody wants to trade in an empty room, and nobody wants to subsidize the room forever.
Revenue is where similar products stop looking alike
PitchBook’s most useful product strategy clue is about rebates. It says “Polymarket’s lower trading rebates” will test whether the company can maintain momentum while retaining more of its fees. Translation for builders: customer acquisition can look heroic when incentives are generous, but the real test starts when the coupons get smaller and the marketplace still has to feel liquid.
That is why the Kalshi and Polymarket comparison is less about who has the prettier odds page and more about who owns the better economic loop. If trading activity creates fees, fees can fund acquisition, and acquisition deepens liquidity, the marketplace starts to compound. If activity depends too heavily on paid incentives, the flywheel behaves more like a treadmill: impressive motion, expensive scenery, little proof that the machine runs on its own.
Liquidity is a product feature, not a vanity chart
Polymarket’s own companies category shows how granular the product surface has become. Polymarket says that category has 500 active markets and more than $44.6 million in trading volume, with examples around outcomes such as which companies will be acquired before 2027. That breadth matters, because every new category is both a customer acquisition wedge and a liquidity fragmentation risk.
Kalshi Research adds another layer to the product question. In a paper based on more than 1 billion trades executed from October 2025 to September 2026, Kalshi Research argues that skilled traders can materially contribute to price discovery, alongside volume, the number of traders, and time to resolution. The product implication is straightforward: market quality is not only about having more users. It is about attracting the right mix of participants at the right moments, then giving them enough depth to make prices worth trusting.
This is where prediction markets start to look like developer platforms or payments networks. The visible product is the interface, but the moat lives in routing, liquidity, trust, compliance, and repeat behavior. A marketplace with many thin markets can feel like a mall with every store open and no shoppers. A marketplace with fewer dense markets can feel smaller, but trade better.
The next product edge may be market design
Axios reported that Kalshi’s chief compliance officer, Sudhir Jain, said Kalshi submitted comments to the Commodity Futures Trading Commission asking it to allow compute markets to relist. Axios described those contracts as markets tied to the future cost of renting GPUs, the chips used to run AI workloads. That is a revealing direction, because it points away from pure attention markets and toward hedging use cases where participants may have an operational reason to trade.
If Kalshi can expand into markets tied to business inputs, its product roadmap starts to look less like a feed of timely questions and more like infrastructure for price discovery. Polymarket’s challenge, based on PitchBook’s rebate comment and its own broad category surface, is different: prove that domestic momentum can persist while the economics tighten. Same stadium, different playbooks.
For product leaders, the lesson is not that every hot marketplace needs a token, a regulator, or a clever odds display. It is that liquidity is the product, monetization is the exam, and incentives are the bill that eventually comes due. Watch the next few quarters for two signals: whether Polymarket can keep activity strong while keeping more fees, and whether Kalshi can turn regulated market design into higher value trading categories.