Polymarket and Kalshi competition fuels high activity September

Polymarket and Kalshi are accelerating their rivalry, as the platforms are fighting for market share and valuations. Kalshi has already expanded its market share of predictions to over 66%, though Polymarket remains relevant for current events. 

Polymarket and Kalshi are intensifying their rivalry, fighting for market share dominance and valuations. Kalshi, which relies on sports betting and gains activity from Robinhood, has grown its market share of predictions to over 66%. 

In September, both prediction markets also achieved new peaks in activity volumes, with $1.44B for Polymarket and $2.74B for Kalshi. It achieved 33.32K markets in September, while Kalshi recently had a spike of new prediction pairs, with 79K daily active markets.

The competition between the platforms accelerated after Polymarket raised $2B for a $9B valuation, while Kalshi raised $300M for a $5B price tag. The end goal is to turn prediction markets into mainstream products, especially in the U.S. market. Prediction platforms are trying to position themselves as trading venues, rather than betting platforms. 

Kalshi moves ahead of Polymarket with bigger share of mainstream predictions

Over the past 12 months, Kalshi has become a mainstream platform, integrated with other apps. Most of the bets on Kalshi are made off-chain, accumulating volumes from mainstream users. 

Polymarket, on the other hand, remains transparent due to its on-chain prediction volumes. The platform remains relevant for breaking news and current events, as well as for user-generated markets. 

The Polymarket platform also gained exposure after exposing the winner of the Nobel Peace Prize hours ahead of the official announcement. It turned out the information was leaked through a website, and taken up by prediction pair traders to scoop up cheap “Yes” tokens.

Kalshi attempts to move its data on-chain

Despite its leading position in terms of volumes, Kalshi recently tried to grow its on-chain presence for more transparency. 

The Kalshi marketplace integrated its services with the Pyth Network oracle, meaning its market data are now transparent and shareable. 

The @PythNetwork oracle integration represents the first step in bringing Kalshi onchain

Now builders have a new tool at their disposal: Kalshi data, anywhere

Start building and join our builders program! https://t.co/TYylHchXRp

— Kalshi Crypto (@Kalshi_Crypto) October 13, 2025

The end goal is for Kalshi to also bring all its markets on-chain for a more transparent track record. Kalshi also aims to become a multi-chain platform, while Polymarket still depends on the legacy Polygon chain. 

Pyth Network’s oracle will be able to deliver contract prices aggregated from over 100 blockchains. This will make Kalshi the go-to source for resolutions on live probabilities and current events. 

The data can be used to create additional trading products based on Kalshi markets, without using the platform directly. Kalshi thus aims to encourage the creation of data-based products while retaining its centralized operations.