Group 1 - Amazon plans to significantly reduce the number of packages it sends through the U.S. Postal Service, which could result in millions of dollars in lost revenue for the agency [1][2] - The e-commerce giant, previously the Postal Service's largest customer, aims to cut postal shipments by at least two-thirds by fall this year, coinciding with the expiration of its contract with USPS [2] Group 2 - The decision to cut back on postal shipments reflects Amazon's ongoing strategy to optimize its logistics and shipping operations [1] - Amazon and USPS have not provided immediate comments regarding this development [2]