Walmart operated a larger booth than at the previous year's convention and reportedly attracted greater visitor interest as representatives discussed the company's emerging collectibles marketplace with attendees. Walmart develops invite-only collectibles marketplaceThe retailer's marketplace remains under development and currently accepts sellers on an invite-only basis as Walmart works to build its presence in the fast-growing collectibles sector. The strategy could help Walmart attract specialist collectibles sellers while expanding the range of higher-value products available through its broader e-commerce ecosystem. Walmart partners with GradedGuard as collectibles demand growsWalmart has also partnered with GradedGuard to produce a limited-edition Walmart-branded plastic protective case designed for PSA-graded cards. Mizuho sees large opportunity in U.S. trading card marketMizuho estimates that the U.S. trading card market is worth between $10 billion and $20 billion, highlighting the scale of the opportunity Walmart could target as it expands its marketplace offering.