Tesco is a large British-based international grocery and general merchandise retailer founded in 1924. It developed rapidly through acquisitions in the 1950s and 1960s and became the largest retailer in the UK by the 1990s. Tesco now operates stores across Europe and Asia, employing over 470,000 people worldwide. While still the top grocer in the UK, Tesco has faced increased competition in recent years from rivals Sainsbury's and Asda, and saw a slight decrease in revenues in 2011. To address challenges, Tesco is investing in improving stores, hiring more employees, and innovating through new online and mobile offerings.