The U.S. Department of Agriculture's (USDA) Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) provides food assistance, nutrition education, breastfeeding support, and health care to participating low-income and nutritionally at-risk pregnant and postpartum women, infants, and children up to age 5. Participants exchange WIC vouchers or electronic benefits for specific WIC foods at commercial retail stores authorized by State WIC programs. Authorized WIC vendors may be large grocers, supermarkets, and supercenters such as Walmart or Target, or small and nontraditional food retailers like convenience and drug stores. In addition, some States authorize vendors that specialize in serving WIC clients, referred to as “above-50-percent vendors” or simply “A50 vendors” because they derive the majority of their food sales from WIC transactions.