Last year was by far Tesco's worst ever. The U.K.'s largest retailer had its biggest loss in its history and was the Global 500's second biggest loser, behind Mexican petroleum company Pemex. On top of a major accounting scandal that led to the departure of several top executives, Tesco has struggled both at home and abroad: the supermarket chain took its eye off the ball in the U.K., losing share to discounters like Aldi, as it looked to expand globally. Growth beyond its domestic market has also faltered. New CEO Dave Lewis, a former Unilever executive, has closed stores and lowered prices to try to reinvigorate the brand