Kalshi Captures 60% Share, Ending Polymarket's Prediction Market Dominance

Kalshi has emerged as the dominant player in prediction market and event-based contract trading, capturing nearly two-thirds of sector volume as regulated platforms gain ground over offshore competitors.

Kalshi Captures 62% Market Share as Prediction Trading Volumes Surge

The CFTC-authorized company accounted for 62% of total prediction market volume from September 11-17, compared to Polymarket's 37% share, according to Dune Analytics data. Kalshi processed over $500 million in weekly trading volume while maintaining average open interest of $189 million.

Polymarket, despite generating $430 million in volume during the same period, showed different trading patterns with an average open interest of $164 million. The disparity points to what analysts describe as "sticker positions on Polymarket and faster turnover on Kalshi."

In recent days, Kalshi’s lead over Polymarket has grown even larger, reaching 65% of the total market share. By comparison, as recently as December 2024, Polymarket accounted for 95% of the market.

“Event contracts have generated high demand because they provide a maximally direct way to get exposure to events that affect businesses, people, and the economy, and they provide the most accurate signal on what the likelihood of future events are,” commented Jack Such from Kalshi, responsible for Business & Media Development, to FinanceMagnates.com.

Such is also confident that “prediction markets will become a trillion dollar asset class.”

Different Trading Behaviors Emerge Between Platforms

The platforms' distinct approaches have created different user behaviors. Polymarket's longer-term markets, often spanning weeks or months, keep user funds locked in for extended periods. This creates higher open interest relative to volume.

Kalshi averaged an open interest-to-volume ratio of 0.29, while Polymarket's ratio hit 0.38. The lower ratio suggests Kalshi users trade more frequently, while Polymarket positions tend to remain static for longer periods.

The trading pattern differences reflect each platform's regulatory environment and market structure. Kalshi operates under U.S. regulatory oversight, while Polymarket has historically served international users through blockchain Blockchain Blockchain comprises a digital network of blocks with a comprehensive ledger of transactions made in a cryptocurrency such as Bitcoin or other altcoins.One of the signature features of blockchain is that it is maintained across more than one computer. The ledger can be public or private (permissioned). In this sense, blockchain is immune to the manipulation of data, making it not only open but verifiable. Because a blockchain is stored across a network of computers, it is very difficult to tamp Blockchain comprises a digital network of blocks with a comprehensive ledger of transactions made in a cryptocurrency such as Bitcoin or other altcoins.One of the signature features of blockchain is that it is maintained across more than one computer. The ledger can be public or private (permissioned). In this sense, blockchain is immune to the manipulation of data, making it not only open but verifiable. Because a blockchain is stored across a network of computers, it is very difficult to tamp Read this Term-based contracts.

Kalshi, however, is also facing lawsuits and controversies in several U.S. states. Allegations of gambling have been further fueled by the fact that Poker legend Daniel Negreanu was recently named the face of the platform.

Polymarket Pushes Back Into U.S. Market

Polymarket isn't conceding ground easily. The platform completed its acquisition of QCX, a regulated derivatives exchange, clearing Clearing Clearing is a general term that simply means many different things depending on the subject and related industry. Most commonly, this refers to the reciprocal exchange between banks of checks and drafts, and the settlement of the differences, or the total of claims settled at a clearinghouse. In finance and banking, the word clearing has different meanings depending on the more specific business model. Moving checks from the bank where they were deposited to the bank on which they were drawn. Th Clearing is a general term that simply means many different things depending on the subject and related industry. Most commonly, this refers to the reciprocal exchange between banks of checks and drafts, and the settlement of the differences, or the total of claims settled at a clearinghouse. In finance and banking, the word clearing has different meanings depending on the more specific business model. Moving checks from the bank where they were deposited to the bank on which they were drawn. Th Read this Term the path for re-entry into the U.S. market after resolving regulatory issues.

The company has also launched earnings-based prediction markets in partnership with social investing platform Stocktwits. The collaboration allows stockholders to hedge earnings risk while providing analysts real-time market sentiment data.

These moves represent Polymarket's attempt to compete directly with Kalshi's regulatory advantage in the lucrative U.S. prediction market space. The platform had previously operated in regulatory gray areas before reaching settlements with U.S. authorities.

The competition comes as prediction markets gain mainstream attention, particularly around political events and corporate earnings. Both platforms have seen substantial growth in user activity and trading volumes throughout 2025.

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