DIY retailer Kingfisher was one of the top performing blue-chips on Wednesday morning after bullish comment on the B&Q owner from HSBC.The bank said Kingfisher's self-help strategies will boost returns in the short term while over the longer term the company should be able to make its size pay and improve long term cash flow.'Competitive advantages should yield over the long term structurally higher returns for shareholders, while its underused balance sheet offers potential for international expansion and/or sector consolidation,' HSBC analyst Paul Rossington said.HSBC has upgraded the stock from 'neutral' to 'overweight'.