The efforts of The Ho-Chunk Nation to secure a preliminary injunction against Kalshi and Robinhood regarding their prediction markets offering have garnered widespread support.

A raft of Indian tribes have thrown their weight behind The Ho-Chunk Nation’s stance in a lawsuit brought at the Wisconsin Western District Court.

On January 6, 2026, several organizations and 16 tribes filed a motion to submit an amicus brief. The brief supports The Ho-Chunk Nation’s motion for a preliminary injunction against Robinhood and Kalshi.

The list of supporters includes: The Indian Gaming Association (IGA), National Congress of American Indians (NCAI), Washington Indian Gaming Association (WIGA), California Nations Indian Gaming Association (CNIGA), Arizona Indian Gaming Association (AIGA), Oklahoma Indian Gaming Association (OIGA), Native American Finance Officers Association (NAFOA), and 16 federally recognized Indian Tribes (Amici Tribes).

The Amici Tribes are: Agua Caliente Band of Cahuilla Indians; Elk Valley Rancheria; Jamul Indian Village of California; Karuk Tribe; Kickapoo Traditional Tribe of Texas; Lytton Rancheria; Mashantucket Pequot Tribal Nation; Mescalero Apache Tribe; Morongo Band of Mission Indians; Pechanga Band of Indians; Picayune Rancheria of Chukchansi Indians of California; Pokagon Band of Potawatomi Indians; Pueblo of Sandia; Seminole Tribe of Florida; Sycuan Band of Kumeyaay Nation; and Tunica-Biloxi Indian Tribe.

The Amici Tribes are 16 federally recognized Indian tribes within the meaning of the Indian Gaming Regulatory Act (IGRA). Each of the Amici Tribes is a separate and distinct tribal government with the sovereign authority to conduct and regulate gaming activities on its Indian lands.

The Amici Tribes state that they all have a direct and immediate interest in maintaining their sovereign rights over gaming, including sports betting, on their Indian lands.

Together, the Tribal Amici all have a shared, strong interest in this case because of its potential to have a significant impact on their or their member tribes’ rights regarding gaming on Indian lands, as well as Indian gaming and tribal governmental revenue as a whole. Such revenue, they say, is vital and provides funding for essential government services, tribal programs, and economic development needed to reach the goals of self-governance and self-sufficiency.

The Tribal Amici state that this case could have a significant impact on other cases in which the Amici Tribes or other tribes across the country seek to regulate gaming activity within their territories.

The necessary implication of a decision in Defendants’ favor is that no tribe, anywhere in the United States, can enforce its own or IGRA’s prohibitions on illegal gaming against those engaged in illegal gaming on tribal lands. A district court’s decision can quickly metabolize into authority in other cases across the country.

The Tribal Amici generally agree with the arguments raised by the Ho-Chunk Nation, they also explain the broader regulatory or commercial context in which a question comes to the court, by elaborating on the overall structure of IGRA, including its authorization of suits to enjoin illegal gambling on tribal land.

Additionally, the Tribal Amici provide practical perspectives on the consequences of potential outcomes, by explaining the jurisdictional void that would result from a finding in favor of Defendants, as well as the profound and negative consequences such a void would have on the ability of tribal governments to fund essential operations.