Amazon shares fall 6% as Trump renews attack

Shares of Amazon.com Inc fell 6% on Monday after US President Donald Trump again attacked the online retailer over the pricing of its deliveries through the United States Postal Service and promised unspecified changes.

"Only fools, or worse, are saying that our money losing Post Office makes money with Amazon," Trump tweeted.

"They lose a fortune, and this will be changed. Also, our fully tax paying retailers are closing stores all over the country...not a level playing field!"

Shares of the company were down 5.9% at $1,362.48, wiping out nearly $45 billion from its market value.

Trump has been vocal about his opposition to Amazon's use of the postal service and Monday's tweet adds to investor worries that the company could see more regulation.

Amazon did not immediately respond to requests for a comment.

On Saturday, Trump tweeted that if the post office "increased its parcel rates, Amazon's shipping costs would rise by $2.6 billion."

The US Postal Service (USPS) in November reported a decline in annual revenue, hurt by a drop in first-class and marketing mail, offset partly by an increase in package delivery.

The postal service has also been posting losses mainly because of payments, more than $5 billion a year as mandated by Congress to prefund the service's future retirees' healthcare.

The passage of postal reform legislation could alleviate USPS's pension obligations, give it more pricing power and allow the agency to be more competitive, analysts said.