Detroit Files Amicus Brief Against Prediction Markets

Jonathan Rodriguez

Written by: Jonathan Rodriguez

Published: Mon Mar 30, 2026, 11:00 am ET

Read Time: 3 minutes

Detroit Files Amicus Brief Against Against Prediction Markets

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Detroit is preparing to make history by becoming the first U.S. city to intervene in prediction market litigation. The city plans to file an amicus curiae (friend-of-the-court) brief in the ongoing case between Coinbase and Michigan state officials. 

The formal brief has not yet been released to the public, as the court-ordered filing deadline is April 3, 2026.

This move underscores Detroit's growing concern about how emerging online trading platforms may affect regulated gambling.

Why Detroit Is Filing an Amicus Brief

Detroit's officials argue that prediction markets could directly impact the city's gaming revenue. Detroit hosts Michigan's three commercial casinos, which collectively generate over $100 million monthly, according to the Michigan Gaming Control Board. 

The casinos contribute approximately $24 million in taxes each month, directly supporting Detroit's Quality of Life and School Aid funds. By protecting these revenues, the city helps fund public schools, police, and other essential services.

Moreover, the city sees unlicensed or federally preempted prediction market contracts as a potential competitive threat to traditional operators. By filing an amicus brief, Detroit aims to safeguard its economic interests and ensure state-regulated gambling maintains a level playing field.

Detroit is not alone in this type of municipal activism. For example, Baltimore recently challenged sweepstakes casinos, signaling a broader trend of cities taking legal action to protect local gambling revenues. 

This growing movement demonstrates that municipalities are increasingly willing to intervene when emerging digital gambling platforms threaten regulated markets.

What the Legal Dispute Is About

The core of the case involves whether prediction market contracts fall under federal regulation or Michigan gambling law. Coinbase argues that its contracts are federally regulated through its partnership with Kalshi, making them exempt from state enforcement. 

In contrast, Michigan officials maintain that contracts tied to sports outcomes fall under existing state gambling laws. Tribal gaming groups support Michigan's stance, warning that unchecked prediction markets could disrupt state-tribal agreements and traditional gambling operations.

Michigan Gambling's History and Online Markets

Michigan has a long history of regulating commercial casinos, dating back to the 1990s. Over the last decade, the state has expanded into digital markets, including US online casinos and US online sportsbooks. These platforms have increased gambling accessibility while maintaining strict regulatory oversight. 

Municipalities like Detroit rely heavily on taxes from these operations to fund local services. This history helps explain why Detroit is taking an active role in emerging gambling-related litigation.

Potential Impact on Prediction Markets in the U.S.

Detroit's intervention could influence how courts across the U.S. interpret prediction market contracts. If cities gain standing to challenge unregulated platforms, other municipalities with significant gaming exposure may follow suit. 

Legal rulings could define whether federal preemption shields platforms like Coinbase from state gambling enforcement. Ultimately, this case may set a precedent affecting the entire US online sportsbook and casino landscape, shaping future regulatory approaches for digital event-based trading platforms.

Detroit's planned amicus brief represents a notable shift in municipal engagement with emerging gambling formats. Alongside cities like Baltimore, Detroit is part of a growing trend of municipalities actively defending regulated gaming against digital competitors.

Jonathan Rodriguez
Jonathan Rodriguez

Jonathan is an avid basketball fan, and is often looking forward to the next upcoming NBA season when not checking players' stats during games. He also likes to keep his ears on the ground for the latest rumblings in the online casino industry.

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