The total quarterly trading volume on prediction markets reached an all-time high of $109 billion in the second quarter of 2026. This marks the fourth consecutive quarter of growth, definitively cementing this segment's status as one of the most dynamically developing categories in the crypto industry.
The figure increased by 39% compared to the first quarter, and on an annualized basis, it grew 18-fold. These numbers are based on an analysis of on-chain data and capital raising data. The key conclusion I draw from this statistic is that the market has ceased to be merely a battle for users. It has clearly split into thematic verticals, each forming its own competitive environment.
Structural Shifts: Kalshi Overtakes Polymarket
Total open interest (OI) on prediction markets reached $1.8 billion by the end of June. This indicator, reflecting the amount of capital in open positions, grew by 54% month-over-month, driven by the start of the 2026 FIFA World Cup in the USA, Canada, and Mexico.
The structure of OI has become much more diversified. For the first time, the platform Kalshi emerged as the leader in this metric, after months of close competition with Polymarket. At the same time, Polymarket maintains a significant lead over other participants, despite a decline in its OI.
Excluding sports markets, activity also noticeably accelerated. Weekly trading volume reached $3.1 billion, of which Kalshi accounted for $2.6 billion and Polymarket only $492 million. This gives Kalshi over 80% of the market by this metric.
Specialization and Capital Inflow
In terms of open interest excluding sports, the picture is much more balanced. Here, Kalshi and Polymarket share the market almost equally, although the former is rapidly increasing its share, gaining 8.5% since the start of the quarter. This indicates faster position rotation and an active speculative flow on Kalshi. Its leadership is linked not so much to displacing Polymarket as to capturing the highest-velocity part of the market.
In crypto prediction markets, the shift towards Kalshi was most pronounced — the platform captured about 42% of the segment from Polymarket. At the same time, the latter retains its position as a "more established crypto-native platform."
Political markets, conversely, remain Polymarket's stronghold. It accounted for approximately 96% of all trading in this segment for the quarter. Trading volume on political markets reached $5.7 billion, of which Polymarket provided $5.5 billion, although this is still below the peak of the fourth quarter of 2024.
The World Cup markets showed explosive growth and proved to be more balanced. Kalshi leads with a volume of $2.8 billion, but Polymarket holds second place with $1.8 billion. Since the start of the tournament, daily volume on prediction markets has increased by approximately 75%.
Investment Interest: The Segment Goes Mainstream
Investor interest in the segment is also confirmed. In the first half of 2026, prediction markets became the most funded crypto category, receiving $1.85 billion, surpassing exchanges ($1.57 billion) and AI ($1 billion).
This suggests that investors are increasingly viewing the segment as a major financial infrastructure rather than a niche area. The quarter's outcome was the division of the market into verticals, where leadership is determined not by brand strength but by liquidity depth and market type.
My opinion: Prediction markets are experiencing not just a boom, but a structural transformation. The division into sports, political, and crypto verticals is a sign of maturity. Kalshi, leveraging its regulated status in the US, is capturing high-frequency trading, while Polymarket remains the center for political and crypto-native bets. Investors should closely monitor this trend: capital flows where there is liquidity, not just a name.