Prediction Market Volume Nears $20B as Polymarket US Takes Bigger Share

Friday through Sunday generated approximately $8.60 billion, or 54.9% of Kalshi's entire weekly volume.

Saturday alone reached $2.90 billion before Sunday's record. The final three days generated more trading than the first four combined.

Trade count also moved higher, from 85.26 million to 88.12 million. Our Kalshi volume page tracks the venue's daily, weekly and monthly trading history.

Polymarket US rises while International falls

The two Polymarket venues moved in opposite directions.

Polymarket US added $491.6 million during the week. Polymarket International lost about $150.6 million.

International volume fell from roughly $1.11 billion to $964.1 million, down 13.5%. Its share of volume across the three platforms slipped from about 6% to 5%.

The available International data doesn't break the decline down cleanly enough by category to say what caused it, so we aren't assigning that drop to sports, crypto, politics or another group of markets.

It does leave a clear split: one Polymarket US just had its strongest week in this dataset while the other dropped below $1 billion.

Kalshi and Polymarket US together now account for just over 95% of the volume tracked across the three platforms.

Kalshi is still the biggest part of that by far. But this week, Polymarket US was where most of the new volume showed up, and combinations were where nearly all of that growth came from.

The number to watch next week isn't whether volume crosses $20 billion. It's whether combinations remain above half of Polymarket US trading.

DeFi Rate tracks daily, weekly and monthly activity across the major venues in its prediction market volume tracker.