Stocks are expected to fall back slightly as investors digest a raft of cautious-to-gloomy updates from the retail sector.Continuing difficulties at the catalogue-based retailer Argos continue to plague its owner Home Retail Group, which has announced an 8.1% fall in sales at the chain to £817m in the 13 weeks to 28 May. On a like-for-like basis, excluding the impact of new openings, sales at Argos were down by 9.6% from the same period the previous year during the period.Pressures on the UK consumer have also contributed to an acceleration in the decline in sales at Trendy sportswear retailer JD Sports Fashion. Like-for-like sales in the period between the end of January and 4 June fell by 2.8% from the same period the previous year.Profits were higher at Halfords in the year to 1 April, but the bike and car parts retailer sees the tough trading environment continuing. Pre-tax profits climbed 7.7% from the previous year to £118.1m on revenues up 4.6% at £869.7m.Spreadbetting firm IG Group expects trading revenue for the year ended 31 May to be 7% ahead of last year, as strong growth in Europe and Singapore offset a weakening performance in Japan.---RG