The downgrade yesterday of Greek sovereign debt by ratings agency Standard & Poor's to a level barely above junk status seems unlikely to prevent shares adding to yesterday's modest gains at the outset, with City traders predicting the top-share index will open around 30 points firmer.Supermarket giant Tesco showed it can still cut it in its home market as it returned to like-for-like sales growth in the UK. In the 13 weeks to 28 May, Tesco's UK like-for-like sales excluding petrol and the impact of VAT grew by a miniscule 0.1%, in line with analysts' predictions, having contracted over the previous quarter. Total sales grew by 7% including petrol and VAT.The Avis car hire brand is set to return to single ownership after US operator Avis Budget launched an agreed £636m bid for Avis Europe, offering 315p cash for each Avis Europe share. The closing mid-market price of Avis Europe on the day before the bid was announced was 196.6p.Oilfield services firm Wood Group has extended its contract with TAQA Bratani Limited, the energy company that is 51% owned by Abu Dhabi Water and Electricity Authority, for a further five years.--jh