USPS Investigating Amazon.com

The third paragraph on page 67 of Amazon.com's annual income filing says, "In January 2009, we learned that the United States Postal Service, including the Postal Service Office of Inspector General, is investigating our compliance with Postal Service rules, and we are cooperating."

Peter Rendina, a Washington, D.C.-based spokesman for the U.S. Postal Inspection Service, said in an interview Tuesday the investigation is "ongoing," but declined to provide details. Some, however, are pointing to the internet retailer's use of bulk mail or media mail services as a possible focus.

Wiener said it's plausible that the investigation has something to do with the postal service's manifest mailing system for bulk shipments.

"While it's hard to imagine that Amazon would do anything inaccurate, because they are accuracy freaks, it's possible that if they're doing fulfillment for smaller resellers, it's hard for Amazon to know if the weight calculations are correct," Wiener said.