U.K. Regulator Probes Facebook, Google Dominance in Advertising

The U.K.’s antitrust authority is starting a long-awaited investigation into the dominance of social media giants including Alphabet Inc.’s Google and Facebook Inc. in digital advertising markets.

The Competition and Markets Authority said that if it found that the companies’ market power was harming competition it would consider bringing in a stricter regulatory regime. The new rules could limit how the firms set prices with advertisers, it said. Some separation of business units may also be appropriate, the regulator said.