2 per cent after the world’s largest traditional retailer missed Wall Street expectations for quarterly comparable sales as rising petrol prices had shoppers reining in spending. The report dragged down the S&P 500 consumer staples and consumer discretionary sectors, which were among the weakest of the benchmark’s 11 major industry indexes. Rival retailers such as Costco, Dollar Tree and Albertsons followed Walmart lower with losses between 1 per cent and 2. The increase in US crude oil above US$87 compounded concerns about the health of the US consumer, according to Mona Mahajan, head of investment strategy at Edward Jones. She noted that investors were already anxious after recent weaker-than-expected retail sales and labour market data for July.