The U.S. Department of Justice is expanding the agency’s review of the Microsoft and Yahoo! Internet-search partnership agreement. The request means regulators’ll do a more extensive examination, rather than approve the deal immediately. Over the course of the review, the companies expect to be asked about their search-engine investments, ad pricing and product plans, a person familiar with the matter said. The outcome’ll shape the future of the market for Internet search ads, where Google has triple the U.S. sales of its two rivals. The companies may face more difficulty proving the deal won’t hurt competition as regulators step up oversight of the technology industry, said Michael Katz, a former chief economist in the Justice Department’s antitrust unit.