US Bookmakers and Tribal Organisations Unite Against Prediction Markets

More than 50 organisations linked to the gambling industry and sport have asked the US Senate to ban sports event contracts on prediction markets, Casino.org reported.

The letter is part of a broader campaign. In 2026, criticism of such platforms has grown noticeably stronger: sports event contracts are increasingly being opposed not by isolated market participants, but by broad coalitions of gambling associations, tribal organisations, regulators, trade unions and sports industry groups. The letter was signed by both commercial gaming groups and tribal organisations.

At the centre of the dispute are Kalshi and Polymarket, two of the best-known prediction market platforms. Kalshi operates in the US under the oversight of the Commodity Futures Trading Commission (CFTC), while Polymarket does not have the same status for US users. But Kalshi’s legal status does not change the substance of the criticism: opponents argue that sports event contracts on both platforms are effectively equivalent to sports betting.

The main complaint is that, according to critics, the platforms allow sports betting to be offered across the country under federal financial regulation rather than through licences issued by individual states.

States fear a loss of control and tax revenue, sportsbook operators point to unequal competition, and tribal organisations see a threat to their existing compacts with state authorities.

Notably, in 2026, state-licensed commercial operators and tribal gaming organisations have increasingly been speaking out against prediction markets with one voice. These are groups that usually defend different interests within the gambling industry.

On this issue, however, their positions have aligned: prediction markets draw customers away from the legal sportsbook market, and take money with them.

For tribal gaming organisations, this is particularly sensitive. Revenue from casinos and partnerships with sportsbook operators often funds healthcare, education, infrastructure and other programmes within their communities.

That is why sports event contracts are not only a competition issue for them, but a threat to the very model of tribal gaming.

A separate set of concerns relates to sport itself. Leagues and players’ unions are worried about contracts on specific in-game events, such as player injuries, refereeing decisions, ejections, penalties or other incidents. In their view, such markets increase the risk of manipulation: a match participant could place a bet on a specific outcome, deliberately influence a particular incident, or help other people win a bet.

^{Kalshi allows traders to buy and sell contracts on the outcomes of sports events}

In 2026, the dispute stopped being a technical question about the status of such contracts. It became a conflict over who should regulate sports betting in the US: states and tribal jurisdictions, or a federal financial regulator.

At the same time, the sports sector is not entirely united: some leagues and players’ unions are not calling for a complete ban on prediction markets, but for strict restrictions on the most sensitive contracts.