Unsurprsingly, the retailing sector is the worst performing sector on Thursday, after Home Retail Group took a dive.Home Retail has taken a plunge after revealing an 8.1% fall in sales at its catalogue-based retailer Argos in the 13 weeks to 28 May. "Trading conditions, particularly at Argos, have proved to be more difficult and volatile than anticipated," chief executive Terry Duddy said. FTSE 250 retailing peers Dixons and JD Sports Fashion are also losing heavily. Blue chip Marks & Spencer is also in the red.Meanwhile, the engineering sector is in demand.Weir Group is the highest riser on the FTSE 100 after its earnings estimates were lifted by RBC Capital Markets.There have been reports today that two companies in China have been given fines of £1m after manufacturing illegal duplicates of Weir pumps. Automotive and aerospace engineer GKN, oilfield engineer Wood Group and industrial engineer IMI are also on the rise. ---BCTop performing sectors so far todayForestry & Paper 6,818.27 +3.43%Automobiles & Parts 5,024.50 +2.82%Industrial Metals & Mining 7,828.38 +2.60%Industrial Engineering 7,321.53 +2.51%Construction & Materials 3,874.09 +2.18%Bottom performing sectors so far todayGeneral Retailers 1,724.35 -1.42%Mobile Telecommunications 3,687.00 -0.29%Alternative Energy null 0.00%Leisure Goods null 0.00%Food & Drug Retailers 4,784.33 +0.01%