Kalshi passed Polymarket for US prediction market demand in October

For the first time since Polymarket took first place in the US, Kalshi outpaced it.

Kalshi led the BAP for the first time since April 2024. Polymarket had carried a majority of US segment demand from May 2024 through September 2026. In October 2026 the order flipped: Kalshi took 51.8% of projected market share (BAP) in the US against 37.5% for Polymarket, with both brands still well ahead of the rest of the board.

The gap had been narrowing for months. Polymarket’s BAP fell from about 79.6% in May 2026 to 54.6% in September, while Kalshi rose into the high twenties and mid-thirties. October was the break: Kalshi’s slice jumped by roughly 23 points MoM, while Polymarket lost another 17 points.

Close image

For example, Novig launched a viral PR campaign with Sindi Suini. As a result, this PM brand reached third in September 2026. Previously Novig took fifth, sixth, or seventh places. This relatively big move is a sign the duopoly was leaking share before October.

Featured materials

• US prediction markets 2026: Kalshi and Polymarket near half of iGaming interest
• Prediction markets outpaced traditional iGaming brands in 47 US states in September
• Polymarket US search demand fell 70% after June