Alphabet Inc.'s GOOGL, +3.39% GOOG, +3.44% Google has been sued for £13.6bn ($16.3 billion) over claims its dominance of the digital-advertising market has amassed "super profits" at the expense of hundreds of thousands of websites and mobile apps in the U.K. The class-action lawsuit, filed Wednesday in the Competition Appeals Tribunal in London, is being brought on behalf of 130,000 businesses that carry online banner ads. A Google spokesman said the company "works constructively with publishers across Europe -- our advertising tools, and those of our many adtech competitors, help millions of websites and apps fund their content, and enable businesses of all sizes to effectively reach new customers.