Largest Companies by Market Cap 2015: Facebook Topples Walmart By: InvestorPlace June 23, 2015 at 09:11 AM EDT Read More >> Related Stocks: Apple Berkshire Hathaway Berkshire Hathaway China Mobile Hong Kong Ltd Exxon Mobil Facebook General Electric Google, Inc. JPMorgan Chase & Co Johnson & Johnson Microsoft Novartis Ag ADR PetroChina Procter & Gamble Wal-Mart Stores, Inc. Wells Fargo