Kalshi vs Polymarket 2026 Volume Comparison Trends

Together, Kalshi and Polymarket own about 97% of all prediction market activity in the U.S. Both are giants now. But they are not the same.

As 2026 progressed, traders moved capital rapidly into event contracts across the spectrum of markets. Kalshi built a commanding lead through consistent expansion while Polymarket delivered strong early results before a sharp slowdown in May. This comparison of January through May performance highlights dissimilar paths and numbers.

Kalshi Claims Dominant Cumulative Volume Lead

Kalshi generated 51.67 billion dollars in notional trading volume (total underlying value of assets under trade) across the first five months of 2026, according to platform trackers. The platform posted steady month-over-month growth and benefited from deep liquidity across categories. Polymarket reached 33.50 billion dollars in the same period, showing strong early peaks followed by a noticeably steep May decline.

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Traders in the U.S. have generally, strongly been drawn to Kalshi’s federally regulated structure and U.S. dollar integration. Polymarket’s crypto-native approach leans toward global flows yet proved more volatile, as detailed in recent analysis.

Monthly Volume Comparison: January to May 2026

Month	Kalshi Volume	Polymarket Volume	Kalshi Market Share
January	9.05B dollars	4.19B dollars	68%
February	9.70B dollars	7.26B dollars	57%
March	13.07B dollars	12.22B dollars	52%
April	14.81B dollars	9.14B dollars	62%
May (through late month)	5.04B dollars	0.69B dollars	88%
YTD Total	51.67B dollars	33.50B dollars	61%

Trackers from The Block confirm Kalshi widened its advantage after March as both platforms set first-quarter records.

Sports Contracts Power Kalshi’s Advantage

Sports event contracts drove more than 80% of Kalshi’s activity, delivering tight spreads and substantial liquidity on major sports leagues events. U.S. based traders engaged heavily with NBA, MLB, and college tournament markets, often pushing single events into hundreds of millions. Polymarket captured meaningful sports volume, especially more globally focus sports like soccer, but relied more on politics, crypto prices, and global events for their growth.

This sports emphasis explains much of the performance gap. Kalshi traders enjoyed reliable market execution on popular sports offerings, encouraging larger positions and repeat activity. Polymarket excelled in longer-dated and international contracts where its diverse, global base added unique value, per detailed 2026 comparisons.

Category	Kalshi Share	Polymarket Share
Sports	80%+	~40%
Politics and Government	~5%	~30%
Finance and Macro	~8%	~15%
Other (Crypto, Weather, Entertainment)	~7%	~15%

Kalshi’s sports focus created a self-reinforcing liquidity cycle that continued attracting traders. For context, the U.S. legal sports betting market in total was $150 billion last year. It’s an enormous market and Kalshi is eating into it at steady and growing rates.

Valuation Trends and Institutional Engagement

Kalshi closed a major funding round in May at a 22 billion dollars valuation, signaling strong investor confidence. Its annualized volume recently exceeded 178 billion dollars, drawing increased hedge fund and asset manager participation. Polymarket explored valuations near 15 billion dollars while retaining appeal among crypto-focused traders.

Needless to say, both major prediction markers are headed in one direction in terms of volume and valuation, and that is up.

Liquidity, Fees, and Trader Experience

Kalshi traders benefited from lower slippage on high-volume contracts and seamless USD banking. Connections with all U.S. banks and credit card companies makes Kalshi and easy signup and funding option for all North American traders. Competitive transaction fees combined and improving volumes across more and more markets make Kalshi the currently preferred market for U.S. traders.

Polymarket offered zero or minimal fees on many markets, suiting high-frequency strategies, though crypto settlement adds minor steps for some users who are not digital currency natives.

Higher open interest on Kalshi reflected greater committed capital and supported longer holding periods with more sophisticated positioning. Kalshi has been actively courting and onboarding institutional traders.

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Polymarket continued shining in extended and international markets, according to in-depth guides.

What the First Five Months Signal for the Rest of 2026

The opening months of 2026 have established Kalshi’s regulated, sports-centric model as the current volume U.S. prediction market leader. Polymarket maintained strong appeal through diverse crypto-integrated offerings and standout peaks, as well as notable global sports trading such as a World Cup Winners market that is already past $1.3 billion in volume.. As institutions allocate more capital, the rivalry promises sharper pricing and richer opportunities for traders.

Results through May position Kalshi ahead while highlighting Polymarket’s resilience in specialized segments. The battle for supremacy between the two main players in the industry continues on. Savvy traders already split activity across both to maximize complementary strengths and identify market variances ripe for trading advantages.