Weekly prediction market volume hit $14.4 billion for the first time last week — up from roughly $5-6B at the start of the year. The previous all-time high, roughly $10B, was set only a week prior.
Total volume across all platforms is now more than 10x what it was a year ago.
Open interest hit $1.6B last week — the third consecutive weekly all-time high.
Unlike volume, open interest can only grow when new positions are opened faster than existing ones resolve, so the growth seen here reflects how more money is being put at stake in these markets.
The chart has grown steadily since last fall. Over that stretch, open interest has increased roughly 8x, from under $200M to $1.6B.
The World Cup is attracting lots of interest and activity, and other areas are growing alongside. Non-sports volume — across categories like politics, economics, geopolitics, and current events — hit $3.6B last week on Kalshi and Polymarket combined. That’s larger than total prediction market volume (sports included) was just last year.
In July 2025, non-sports weekly volume was around $200M. It has grown roughly 18x since then, with the trajectory steepening sharply this month.
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Acknowledgments: Data and charts by Ryan Holloway and Robert Hackett (a16z crypto features editor and head of special projects).
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