U.S. stocks fell, halting a three- day rally, as United Parcel Service Inc. (UPS) slumped, economic reports missed estimates and uncertainty grew over how much progress European leaders are making in debt-crisis talks. UPS, whose deliveries make it a proxy for the economy, lost 2.1 percent as international shipping growth began to cool while U.S. expansion stagnated. 3M Co. (MMM), the maker Scotch-Brite sponges, sank 6.3 percent after cutting its profit forecast. Netflix Inc. (NFLX) plunged 35 percent as the company projected losses in 2012. Amazon.com Inc. (AMZN) tumbled 14 percent after the close of regular trading as earnings missed analysts’ projections.