CarGurus shares rocket 80% on their first day of trading By: MarketWatch October 12, 2017 at 14:01 PM EDT The online marketplace for new and used cars is enjoying the best-performing IPO in the U.S. so far this year in terms of offer-to-opening trade. Read More >> Related Stocks: Cargurus Inc Cl A Roku Inc Snap Inc Standard & Poors 500 Switch Inc TripAdvisor