The rise of AI-led shopping is posing a conundrum for retailers like Walmart and Amazon: how to enable AI agents to shop on their websites without threatening their lucrative advertising revenue and the customer data that fuels it, according to Reuters. Walmart and Amazon are the world's two largest retail media businesses, with a combined 88% share of the estimated $74.4 billion in US retail media spending, per Emarketer projections. Morgan Stanley researchers said in July these agents could account for 10% to 20% of US e-commerce spending by 2030. Amazon has blocked Meta's recently released Muse, saying it appeared to have accessed its online store without authorization, capturing and storing customer credentials; Meta declined to comment. Amazon also won a court order blocking Perplexity's shopping agent Comet in March, though the 9th US Circuit Court of Appeals overturned the ban in August, a decision Amazon said it disagreed with. Walmart, conversely, rolled out infrastructure on October 21 to enable third-party agentic commerce, creating a profile for each agent linked to the shopper's Walmart account, with consumers able to approve purchases or set spending limits. Amazon CEO Andy Jassy said last week there is no meaningful effect yet on Amazon ads from third-party agents, though the company's 11% year-over-year growth in advertising revenue for the third quarter was its slowest pace in nearly four years, LSEG data show.