More than half of the states in the United States have joined an unprecedented lawsuit against Meta, accusing the parent company of Facebook and Instagram of deliberately designing addictive products that targeted young users and caused them harm.

The jury trial begins Tuesday in federal court in Oakland, California, and is expected to last six to eight weeks. Witnesses are expected to include Meta CEO Mark Zuckerberg, Instagram CEO Adam Mosseri and former Meta employee and whistleblower Arturo Béjar.

“Meta designed a dangerous product for young users, knew it to be dangerous, and then lied to children, families and the community about how dangerous it was,” said Rob Bonta, California’s attorney general.

The trial will be led by attorneys representing California, Colorado, Kentucky and New Jersey, while the lawsuit involves all 29 states as part of a multidistrict litigation case.

The 233-page lawsuit, originally filed in October 2023, alleges that Meta routinely collects personal data from children under 13 without parental consent, violating federal and state laws. The states also accuse the company of knowingly retaining features they say are harmful to young users, arguing that Meta has prioritised profits and sought to maximise its financial returns.

The case could have significant financial and operational consequences for the social media giant.

Attorneys general argue that Meta could face damages of up to $200 billion if found liable, an amount roughly equal to the company’s total revenue in 2025.

Beyond financial penalties, the states are seeking an order requiring Meta to redesign its products to make them safer for children. Such measures could have a more lasting impact on the company’s platforms than a monetary fine.

Meta has denied all the allegations, arguing that the states are pursuing an excessive financial settlement rather than focusing on the facts or applicable law.

“The State AGs may call this a landmark case, but their limited claims are unsubstantiated and their financial demands are vastly disproportionate,” the company said in a statement. “The AGs offer no proof anyone in their states was misled, claim benign features like having an additional Instagram account somehow harmed their residents, and attempt to penalize Meta for industry-wide challenges like age verification.”

The attorneys general also allege that Meta “developed and refined” psychologically manipulative features aimed at keeping users on its platforms for as long as possible. These include infinite-scrolling recommendation feeds, frequent notification alerts, thumbs-up “likes” and visual filters that allow users to alter their appearance.

The lawmakers argue that young people are particularly vulnerable to these features, warning that excessive time spent online can contribute to depression, anxiety, eating disorders and other mental health problems.

“The State AGs may call this a landmark case, but their limited claims are unsubstantiated and their financial demands are vastly disproportionate,” the company said in a statement. “The AGs offer no proof anyone in their states was misled, claim benign features like having an additional Instagram account somehow harmed their residents, and attempt to penalize Meta for industry-wide challenges like age verification.”