Retailers' profits are seeing a pinch as inflation cools — and in some categories, even reverses.For Costco, raising membership fees can offset some of that deflationary bite.The wholesale club prides itself on ultra-low markups, and membership fees help it do that. Sign up to get the inside scoop on today’s biggest stories in markets, tech, and business — delivered daily. Read preview Thanks for signing up! Access your favorite topics in a personalized feed while you're on the go. Email addre ...