Top rating agency Fitch has changed its outlook on Tesco from stable to negative over concerns about the level of investment Tesco is pumping into overseas operations that will not contribute to its bottom line for several years. Although the maturity of the UK market means overseas expansion is essential for long-term sales growth, there are concerns that money Tesco ought to be spending on its domestic estate is going abroad, said the agency. While Tesco remains the undisputed leader in the UK, is also "difficult to ignore the improving like-for-like sales increases that Sainsbury, Asda, et al have announced during the past year," said the agency. {{NEWS }}