FYI for FBM sellers: Amazon says that starting December 18, 2026, most US returns for seller-fulfilled orders will require a prepaid return label. Within seven calendar days of a return request, sellers must upload the label through Manage Seller-Fulfilled Returns or issue a full refund without requiring the item back. If neither happens, Amazon says it may automatically issue a returnless refund and deduct the amount from the seller’s account. Heavy and bulky items are temporarily excluded. Labels sent outside Amazon’s returns workflow won’t count.