As we've already seen in this series, US food at home prices declined for a second straight month in April, by 0.2%. Last month, Business Insider, citing the Wall Street Journal, said Wal-Mart (WMT), the world's largest retailer (XRT), has asked its suppliers to redirect spending on marketing and store displays to lower prices for products. Wal-Mart wants to pass cost savings down to its customers and compete more effectively with its grocery rivals.