Debt traders are indicating FedEx Corp., after an eight-year drought, is headed for a second 2012 credit upgrade as rising online commerce keeps ground deliveries growing even as the U.S. economy shows signs of faltering.

Credit-default swaps linked to debt of the operator of the world's largest cargo airline have traded at levels implying it should be graded A3 since May 7, according to Moody's Corp.'s capital markets research group, one level higher than its Baa1 mark from the company's rating arm. FedEx's 8 percent bonds due in January 2019 yield 2.59 percent, less than the 2.85 percent on all A rated corporates due in five to seven years, according to Bank of America Merrill Lynch index data.

FedEx, founded by Chief Executive Officer Fred Smith four decades ago, is profiting from rising sales at online retailers such as Amazon.com Inc. that use it to ship goods. The company's ratio of debt to earnings before income, taxes, depreciation and amortization has declined to 0.32 times on May 31 from 1.10 times in 2004 as income rose in each of the past three years.