Regulatory-compliant liquidity boosts Kalshi ahead of Polymarket

Analytics sources indicate that in late September 2025, Kalshi surpassed Polymarket in U.S. trading activity, securing 62–62.2% of the on-chain prediction market share.

and The Block report that Kalshi achieved weekly trading volumes above $500 million and maintained an average open interest of $189 million, outstripping Polymarket’s $430 million in trades and $164 million in open interest. This marks a notable shift in liquidity, attributed to Kalshi’s regulated status in the U.S. and its emphasis on high-frequency, short-duration markets.

The difference in open interest-to-volume ratios highlights distinct trading patterns between the two. Kalshi’s ratio of 0.29 points to brisker trading compared to Polymarket’s 0.38, indicating that Kalshi’s users tend to trade more actively, while Polymarket’s offerings—often lasting weeks or months—result in capital being held for longer. This trend supports Kalshi’s goal of appealing to both retail and institutional traders seeking regulatory assurance and ample liquidity, especially in political and sports-related markets.

Kalshi’s recent growth aligned with the beginning of the 2025 NFL season, which led to a surge in sports-focused trading. Since the season began, the platform has processed $441 million in trades, with CEO Tarek Mansour comparing the first week’s activity to that of a U.S. election. Meanwhile, Polymarket, having re-entered the American space through its purchase of the regulated derivatives exchange QCX, has obtained a CFTC no-action letter but faces ongoing regulatory scrutiny. Authorities in Massachusetts have filed suit against Kalshi for allegedly running unlicensed sports betting operations, claiming it operates in a similar manner to online

sites.

Shifts in company valuations illustrate the platforms’ diverging paths. Kalshi recently secured $185 million in new funding led by Paradigm, bringing its valuation to $2 billion, while Polymarket is believed to be seeking a $9–$10 billion valuation as it returns to the U.S. market. Despite facing regulatory obstacles, Polymarket’s QCX acquisition and CFTC approval put it in a position to operate under federal rules. At the same time, Kalshi’s institutional alliances—including its first dedicated market maker Susquehanna Government Products, as well as partnerships with

and Base—highlight increasing mainstream acceptance of regulated prediction platforms.

This rivalry reflects wider developments in the crypto and fintech industries, where regulatory compliance is now a key requirement for institutional involvement. Kalshi’s U.S.-focused, KYC-enforced platform stands in contrast to Polymarket’s international, pseudonymous model. Observers note that while Polymarket’s inclusion of global and geopolitical topics draws a varied user base, Kalshi’s regulatory advantages and superior liquidity are redefining the industry landscape. As both companies gear up for more fundraising and growth, the prediction market sector is on track for broader adoption, fueled by its overlap with crypto, AI, and real-time financial tools.