Amazon.com must pay nearly $300 million in back taxes to Luxembourg, European authorities said Wednesday after concluding the tech giant benefited from an illegal tax arrangement dating to 2003.

The company, which is being fined following a three-year investigation, is the latest in a string of U.S. technology firms to face tax-related penalties in the E.U. An Amazon spokeswoman said the company is considering an appeal. (Jeff Bezos, chief executive of Amazon, also owns The Washington Post.)

According to the European Union, Amazon put “the vast majority” of its profits in a Luxembourg-based holding company, which allowed the company to avoid paying taxes on the bulk of its European profits between 2006 and 2014.