Tesco is a large international grocery and general merchandise retailer headquartered in the UK. It operates over 5380 stores across 14 countries, with the largest presence in the UK, Ireland, Malaysia, and Thailand. Tesco began as a small grocery stall in London in 1919 and has expanded significantly over the decades through acquisitions and new store openings, becoming a global retail leader and pioneering strategies like loyalty programs and online shopping. The document provides an overview of Tesco's history, operations, formats, competitors, and strategies.