Kalshi overtakes Polymarket in global trading volume

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2025/12/02: Kalshi and Polymarket hit record US$10 billion trading volume for November 2026/02/11: Kalshi reports over US$1 billion Super Bowl trading volume 2026/03/25: Kalshi and Polymarket introduce new insider trading restrictions 2025/10/24: NHL signs multi-year deals with Kalshi and Polymarket

The Backstory

How the volume race flipped

Prediction markets have spent the past year moving from a niche corner of finance and betting to a headline business. That surge set the stage for today’s reshuffling in market leadership. Growth accelerated in late fall when the two biggest operators, Kalshi and Polymarket, posted a record month with a combined $10 billion in November trading. The Block’s data showed Kalshi leading that jump, with Polymarket also hitting a new high as retail traders chased news cycles, elections and sports. Analysts began calling the category an emerging duopoly, and the funding environment followed. Polymarket struck brand deals with tech platforms, while Kalshi raised fresh capital and deepened product integrations, positioning both to convert attention into liquidity.

What has changed since then is the balance of execution and access. Kalshi’s ability to operate broadly in the United States since 2020 has given it a regulatory runway to build compliance processes, deepen relationships and scale its catalog. Polymarket’s reliance on blockchain rails has been a differentiator for some users, but it has also introduced complexity at moments when uptime and U.S. market traction mattered most. A long U.S. pause tied to federal enforcement and a staggered reentry have slowed its domestic momentum even as the brand remained visible through high-profile partnerships. Those operational realities are now showing up in market share.

A duopoly hardens, then diverges

The November spike was not a one-off. Product velocity and media moments kept volumes elevated into winter. Kalshi used cultural tentpoles to grow its user base and familiarity with event-based contracts. During the Super Bowl, the platform booked more than $1 billion in daily trading, a 2,700% year-over-year jump as users speculated on game outcomes and halftime entertainment. That day underscored both Kalshi’s capacity to marshal liquidity and the operational strain of viral traffic, with the company acknowledging delayed deposits even as it emphasized system safety.

Polymarket continued to post gains, but the gap in U.S. distribution and timing of product updates widened. In a category where depth of order books and confidence in settlement determine user behavior, even brief disruptions or postponed upgrades can move traders to the venue with the tightest spreads and most predictable execution. The consequence: a duopoly that looked balanced in late fall has shown signs of divergence, with Kalshi translating news-driven surges into stickier share.

Sports deals bring legitimacy — and backlash

As prediction markets sought mainstream recognition, sports became a proving ground. The NHL signed multi-year partnerships with Kalshi and Polymarket, granting access to league data and branding across regular-season broadcasts and marquee events. For the platforms, those rights promised awareness, official data feeds and a pipeline for new, sanctioned markets tied to a national schedule. Executives framed the deals as validation of prediction markets as a trustworthy way to engage fans.

The traditional gambling industry pushed back. The American Gaming Association called the NHL tie-ups “deeply concerning,” arguing that prediction markets were operating outside state-by-state licensing norms even as they relied on federal permissions. Nevada regulators reminded licensees that sports event contracts would be treated like wagers and restricted to approved operators in the state. The push-pull highlights a central fault line: prediction markets are building national brands under a federal commodities framework while sportsbooks navigate a state patchwork. Every league deal heightens that tension — and raises the stakes for how regulators define the boundary between derivatives and gambling.

Insider risk tests market integrity

With scale has come scrutiny over whether event-based contracts can be gamed by those with nonpublic information. Ahead of and after major cultural moments, concerns spiked about employees at brands featured in ads, athletes or political staffers trading on foreknowledge. In response, both platforms tightened their rules. Kalshi and Polymarket introduced new insider trading restrictions that expand eligibility screens, clarify prohibited activity and add whistleblower tools on market pages. Kalshi said it was applying the same surveillance standards used by major U.S. exchanges and had conducted hundreds of investigations.

The political blowback showed the limits of platform-level policies. Rep. Alexandria Ocasio-Cortez said Kalshi’s measures were “not enough,” pointing to a broad universe of connected individuals who could trade on sensitive information. Lawmakers also floated a bill to ban sports betting on prediction markets, further blurring lines between federal market oversight and state gambling rules. The regulatory message was clear: growth would be judged not just on volumes but on demonstrable integrity controls that prevent manipulation while preserving the informational value that prediction markets promise.

Regulators shape the runway

Even as national volumes have swelled, state regulators have issued warnings that could limit distribution and partnerships. Pennsylvania’s gaming authority cautioned casinos and sportsbooks against involvement with prediction markets, arguing the platforms sit outside the state’s consumer protection, responsible gambling and tax systems. Other states, including Connecticut, Nevada and New York, have active disputes with operators over whether sports event contracts should be classified as unlicensed gambling or federally regulated financial products.

Consultants see a ceiling — and a catalyst — in that uncertainty. A forecast from Eilers & Krejcik projects that annual prediction market trading could climb to about $1 trillion by the end of the decade if legal clarity and consumer demand align, with sports driving roughly 44% of activity. The firm also warns that regulatory setbacks could delay or derail the trajectory. For now, the platforms are racing to entrench themselves with retail traders, leagues and media partners while building compliance muscle to withstand the next wave of scrutiny.

What the shift signals

Kalshi’s recent edge in trading activity reflects three converging forces: consistent U.S. market access, timely product execution and the ability to convert mass-culture moments into liquidity. Polymarket’s brand momentum and partnerships have kept it competitive, but delays, infrastructure choices and a slower U.S. rollout have weighed on near-term share in a market where reliability and speed compound.

The stakes are bigger than a leaderboard. Prediction markets are testing whether a federally supervised, event-based marketplace can scale nationally while coexisting with state gambling regimes. If integrity rules mature and legal boundaries settle, the category could evolve into a mainstream instrument for price discovery on news, elections, sports and culture. If not, fragmented access and enforcement risk could cap growth and push users to gray markets. Today’s flip in volume leadership is a snapshot of that broader contest — execution and trust on one side, regulatory reality on the other — and it will determine who defines the rules as the industry moves from hype to habit.