For every Amazon package it delivers, the Postal Service loses $1.46

An old salesman joke: A salesman says, "We sell below cost." A customer asks how he can do that. "Simple," he says. "We buy below cost."

For a day or so last week, Jeff Bezos passed Bill Gates as the richest man in the world. And that's pretty much how he did it.

Bezos runs Amazon, which is primarily a shipping business. It relies on the U.S. Postal Service to deliver two-thirds of its packages. In many places now, it locates a depot near a post office, presorts the packages, and delivers them to the post office. The Postal Service, which has a monopoly on last-mile delivery, does the rest.

The Postal Service is happy because it can report healthy increases in sales in the package delivery department. Postal employees are happy because it means work seven days a week — the Postal Service operates on Sundays almost solely to deliver for Amazon.

And Amazon is happy because it has a deal that takes advantage of a loophole in the law that gives it a taxpayer-subsidized deal none of its competitors could get or match.