The practice known as “drip pricing” violates consumer protection laws in the nation’s capital, Attorney General Brian Schwalb said.

“StubHub intentionally hides the true price to boost profits at its customers’ expense,” he said in a statement.

The company did not immediately respond to an email seeking comment.

The mandatory “fulfillment and service” fees are hidden until the end of a lengthy online purchasing process that often requires more than a dozen pages to complete as a countdown timer creates a sense of urgency, Schwalb said.

That makes it “nearly impossible” for buyers to know the true cost of a ticket and compare to find the best price, he said. Fees vary widely and can total more than 40% of the advertised ticket price, the lawsuit alleges.

StubHub is one of the world’s largest resale platforms for tickets to sports, concerts, and other live events.

Sally Greenberg, CEO of the nonprofit advocacy group National Consumers League, applauded the lawsuit. “Hidden fees in the ticketing industry have truly gotten out of control. The price that is advertised is the price that we should pay — full stop,” she said. Ticket fees were also part of a sweeping antitrust lawsuit the Justice Department filed against Ticketmaster and its parent company in May.

StubHub used to advertise the “all-in” cost of a ticket about a decade ago, but changed after finding that people are more likely to buy tickets at higher prices with the “drip pricing” model, he said.

Washington residents’ per-capita spending on live entertainment outpaces that of many other major U.S. cities and since 2015, StubHub has sold nearly 5 million tickets in Washington and reaped about $118 million in fees, the suit states.

The lawsuit seeks damages and to block the pricing practices. Schwalb settled another lawsuit last year with the Washington Commanders over fans’ season ticket deposit money.