Tesco is a large public retail company founded in 1919 in London. It operates 6,351 stores worldwide across several countries and has over 519,671 employees. Some key facts: - Tesco is the 3rd largest retailer globally and was the 2nd largest in terms of profits. - It has expanded internationally since the 1990s and now operates in several markets outside the UK. - In its home market of the UK, Tesco has a 30.2% market share of the supermarket sector as of 2012, making it the largest supermarket chain.