According to USDA Economic Research Service 2019 Annual Retail Trade Survey retail food and non-food products sales by grocery stores attained $717 billion in 2019.  Grocery stores amounted for 92 percent of sales, specialty foods store 3.3 percent and convenience stores 4.6 percent.  For the purposes of the survey warehouse clubs were incorporated with conventional grocery stores.

Total U.S. food sales at supermarkets, warehouse clubs and supercenters reached $653 billion in 2019.  The twenty largest food retailers represented 65.1 percent of total food sales in 2019 with sales amounting to $410 billion.  This share increased from 35 percent in 1990.  The top four retail food retailers increased market share from 13 percent to 32 percent over the period 1990 to 2019. 

Walmart is the largest U.S. retailer of grocery products followed by Kroger, a traditional chain.  Growth among the top eight was accomplished through consolidation.  Delhaize was acquired by Ahold in June 2015, Safeway was folded into Albertsons in the same year and in 2017 Amazon purchased Whole Foods Market.  In total, more than 300 industry mergers and acquisitions were documented in 2019.