Opening arguments began Tuesday in a federal court in California for a landmark trial accusing Meta Platforms of contributing to a teen mental health crisis. A coalition of 29 state attorneys general alleges that the parent company of Facebook and Instagram illegally collected and exploited children's data, designing its platforms to be addictive and causing anxiety, depression, self-harm, and suicide among young users.

Meta could face "astronomical" damages, with the states estimating potential penalties could reach $1.4 trillion, a figure close to the company's market capitalization. However, the states suggest a more realistic outcome if Meta loses the case would be $200 billion in damages, which would still be an unprecedented sum.

New Mexico Attorney General Raul Torrez, who recently secured a $567 million judgment against Meta in a similar state trial, indicated that the potential for a significant court loss for the company is being underestimated by Wall Street. "You could wake up with a headline judgment that is, as I've said, astronomical," Torrez told CNBC.

The lawsuit, first filed in 2023, accuses Meta of misleading the public about the safety risks associated with its apps. California Attorney General Rob Bonta stated, "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. We are ready to hold Meta accountable for its role in fueling the mental health crisis of American children and look forward to trial."

While a jury will hear the arguments and provide an advisory verdict, the final decision on damages and any required business practice changes will rest with District Judge Yvonne Gonzalez Rogers. The states are seeking to compel Meta to delete any illegally obtained data from users under 13 and to stop using algorithms trained on that data. They also want a court order prohibiting the use of certain addictive design features, such as infinite scroll and autoplay.

Mark Zuckerberg and Instagram chief Adam Mosseri may be called to testify. Arturo Bejar, a former Meta safety researcher who testified in the New Mexico trial, is also expected to be a key witness. Bejar previously accused the company of exposing his teen daughter to "predators."

Meta has denied all allegations, with a company spokesperson stating that the attorneys general are seeking damages beyond the scope of the case and have not provided evidence of real-world harm caused by the company's apps. "Rather than sticking to the facts or the law, the states have instead decided to chase an outlandish payout," the spokesperson said. "We stand by our record of creating strong protections for teens, and look forward to making our case in court."

This trial is seen by critics as a pivotal moment for the social media industry, drawing comparisons to the "Big Tobacco" litigation. Meta and Google were previously ordered to pay a combined $6 million in damages in a California state court case involving a young woman who alleged social media addiction. Thousands of lawsuits against Meta and other social media companies are pending across the country.