Shares of Trivago NV (ADR) (NASDAQ: TRVG), the relatively small online travel agent (OTA) company headquartered in Germany, rose as much as 15% today after the company updated full-year 2017 guidance on the back of a strong start to the year. Expedia (NASDAQ: EXPE), one of the largest OTA players, is Trivago's largest stakeholder as it owns more than 60% of the company.