Costco tariffs 2026 has become one of the most consequential and commercially complex storylines in the entire American retail landscape — producing Supreme Court rulings, class action lawsuits, potential billion-dollar refunds, and a masterclass in how the world's most powerful warehouse retailer protects its members when global trade policy turns chaotic. If you are a brand operating in the consumer packaged goods space and selling or seeking to sell through the Costco chan