Amazon, Walmart, Kroger, Uber, Target, Instacart, DoorDash, Costco. The fastest-growing major ad category in U.S. history — who runs it and what brand teams need to know.
The inaugural Retail Citation Share Index 2026 — which retailers ChatGPT, Claude, Gemini, Perplexity, AI Overviews cite. Walmart owns scale. Amazon owns e-commerce. Target owns design. Costco owns value. Home Depot owns DIY. Kroger owns grocery.
Walmart $681B. Target same-day $9B+. Kroger digital $13B. Costco, Sam's Club, Best Buy, Home Depot, Lowe's. The 2026 retail convenience infrastructure and the EPR Retail Convenience Scorecard.