“Without the ability to transfer data across borders, the internet risks being carved up into national and regional silos, restricting the global economy and leaving citizens in different countries unable to access many of the shared services we have come to rely on,” Nick Clegg, Meta’s president of global affairs, and Jennifer G. Newstead, the company’s chief legal officer, said in a statement.

The ruling, which is a record fine under the General Data Protection Regulation, or G.D.P.R., could affect data related to photos, friend connections and direct messages stored by Meta. It has the potential to bruise Facebook’s business in Europe, particularly if it hurts the company’s ability to target ads. Last month, Susan Li, Meta’s chief financial officer, told investors that about 10 percent of its worldwide ad revenue came from ads delivered to Facebook users in E.U. countries. In 2022, Meta had revenue of nearly $117 billion.

Meta and other companies are counting on the new data agreement between the United States and the European Union to replace the one invalidated by European courts in 2020. Last year, President Biden and Ursula von der Leyen, the president of the European Commission, announced the outlines of a deal in Brussels, but the details are still being negotiated.

Without a deal, the ruling against Meta shows the legal risks that companies face in continuing to move data between the European Union and United States.

Meta faces the prospect of having to delete vast amounts of data about Facebook users in the European Union, said Johnny Ryan, senior fellow at the Irish Council for Civil Liberties. That would present technical difficulties given the interconnected nature of internet companies.