IF you are thinking of selling your second-hand car then some news from Auto Trader, the UK and Ireland's largest digital automotive marketplace, might just interest you. According to the latest data from Auto Trader, the 2015 Kia Sorento (diesel automatic) is their fastest-selling used car. It means the popular Korean SUV is selling by more than a week faster on average than any other second-hand car of a similar age and value. Auto Trader’s Fastest Selling Index, which tracks the potential speed at which vehicles will sell based on live supply and demand in the market, shows that the Sorento is in good company. In total, seven 4x4s and crossovers made it on to the national top 10 list of fastest sellers in August. The speed at which SUVs are selling reflects the huge levels of consumer demand in the market. Based on searches and advert views they are the most in demand body type on Auto Trader, and by some margin, with levels increasing over 14 per cent year-on-year last month. The second-placed car type is hatchback, followed by coupes, saloons, estates and then convertibles with people carriers the only body type to see levels of demand fall this month.