Polymarket US traded $7.1 billion in contracts between August 27 and September 25, 2026, with $2.4 billion paid out, accounting for 10% of overall prediction market volume. This represents a 93% increase compared to the previous 30 days. The peak trading day was September 20, 2026, with $526 million in transactions. As of September 24, Polymarket US had an open interest of $76 million and recorded a total of 413,506 trades during the timeframe.
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In the last week leading up to September 26, 2026, Polymarket US handled $2.6 billion in volume with $764 million paid out. For 2026 overall, it reported $19.2 billion in contracts traded and $7.9 billion paid out. July was noted as its busiest month, with $5.0 billion traded.
The volume breakdown during the established date range shows that the sports category dominated, constituting $7.0 billion or nearly all trading volume among other categories such as technology, politics, economics, and finance, which saw significantly lower figures.
In terms of market activity, the most traded events included various sports matchups, with notable volumes in the New York vs. Detroit game at $186,000 and the Los Angeles vs. Denver matchup at $134,000.
Polymarket US’s overall market share of prediction trading increased to 12.6% as of September 14, 2026, compared to 7.2% at the start of June. Since launching in May 2026, the platform has rapidly gained traction within the prediction market landscape.