J Sainsbury PLC (LSE:SBRY), too, has seen its shares gain 4% since its update yesterday. Arguably Sainsbury's delivered a less positive update than larger rival Tesco, with its grocery business doing all the heavy lifting to make up for a disappointing Christmas for Argos, while M&S beat consensus expectations in both its Food and Clothing & Home businesses and tweaked its profit guidance upwards. However, some investors and analysts were clearly expecting better, while also eyeing tougher times ahead.