A D.C. court ruled today that four major online travel companies have been bilking the city out of millions in hotel room taxes.

D.C. Superior Court Judge Craig Iscoe found today that the four companies—Expedia, Orbitz, Priceline.com, and Travelocity—have been skirting the city’s 14.5 percent occupancy tax by paying the tax on the wholesale rates they negotiate with local hotels, not the higher rate they charge customers when they book rooms.

As a consequence, said D.C. officials in a lawsuit filed last year, the city was missing out on between $4 and $10 million a year in taxes.

“The Court’s ruling today is an important step in our efforts to ensure that the District receives the substantial sums it is owed by online companies selling hotel rooms in D.C.,” said Attorney General Irv Nathan in a statement.

According to the Washington Business Journal, the decision goes against other recent judicial rulings related to what low-cost travel websites owe in taxes:

“The interesting thing about this case is that it is almost completely out of line with almost every other decision we’ve seen over the last year,” said Joe Rubin, director of the D.C.-based Interactive Travel Services Association, which represents the interests of OTCs.

Just last week, for example, a three-judge panel of the U.S. Court of Appeals in Ohio affirmed a lower court ruling that OTCs do not owe hotel taxes on the retail mark-up.

The decision did not resolve how much D.C. is owed in back taxes, nor whether the four companies will have to pay negligence or fraud penalties.