**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** SUPPLEMENTAL NUTRITION ASSISTANCE PROGRAM (SNAP) IS THE MOST IMPORTANT ANTI-HUNGER PROGRAM IN THE UNITED STATES. SNAP ALLEVIATES FOOD INSECURITY BY PROVIDING PARTICIPANTS WITH MONTHLY BENEFITS TO PURCHASE FOODS USING AN ELECTRONIC BENEFIT TRANSFER CARD. HOWEVER, NOT ALL FOOD RETAILERS PARTICIPATE IN SNAP, AND THE IMPORTANCE OF SNAP-AUTHORIZED RETAILERS IS NOT FULLY UNDERSTOOD IN THE LITERATURE. THE OVERARCHING GOAL OF THE PROPOSED RESEARCH IS TO DEVELOP A COMPREHENSIVE ANALYSIS OF THE SNAP-AUTHORIZED RETAILERS' COMPETITIVE EFFECTS IN LOCAL GROCERY MARKETS AND THEIR ROLE IN AFFECTING KEY PROGRAM OUTCOMES SUCH AS SPAP PARTICIPATION AND FOOD SECURITY. THE OBJECTIVES SUPPORTING THIS GOAL ARE 1) ASSEMBLE A UNIQUE DATASET TO DOCUMENT THE ENTRY/EXIT OF SNAP-AUTHORIZED STORES OVER TIME AND ACROSS LOCAL FOOD MARKETS AND EXAMINE HOW RETAILER SNAP AUTHORIZATION IS ASSOCIATED WITH CHANGES IN THE COMPETITIVE ENVIRONMENT AND SOCIOECONOMIC VARIABLES; 2) ANSWER WHETHER FOOD PRICE LEVELS AND INFLATION RATES DIFFER FOR SNAP-AUTHORIZED STORES RELATIVE TO NONAUTHORIZED STORES; 3) ESTIMATE THE EFFECTS OF RETAILER SNAP AUTHORIZATION ON FOOD VARIETIES SOLD AND COMPETITORS' STRATEGIC RESPONSES; 4) ESTIMATE THE IMPACT OF SNAP AUTHORIZATION ON LOCAL MEASURES OF SNAP PARTICIPATION AND FOOD INSECURITY; 5) SYNTHESIZE OUR FINDINGS AND DEVELOP POLICY RECOMMENDATIONS REGARDING SNAP AUTHORIZATION AND POLICIES DESIGNED TO ADDRESS FOOD SECURITY.