Postal Service Loss Grows as First Class Mail Declines - Bloomberg The U.S. Postal Service, which predicts that by the end of September it will be unable to make health-benefit payments for future retirees, said its first- quarter loss widened as first-class mail volumes declined. The volume of first-class mail, the agency’s most profitable service, fell 6 percent in the quarter, Chief Financial Officer Joseph Corbett said today at a postal board meeting in Washington. Bulk mail, which is cheaper and brings in less revenue, advanced 9 percent, he said. It takes the addition of three pieces of bulk mail to make up for the loss of one first-class letter, he said.