Update (4/2/2018 10 am ET): With Amazon shares already heading lower thanks to Trump's weekend twitter thrashing, the president has again chimed in Monday morning, tripling down on his recent threatening rhetoric toward the e-commerce giant.

According to Trump, "only fools, or worse, are saying that our money losing Post Office makes money with Amazon. THEY LOSE A FORTUNE, and this will be changed."

Only fools, or worse, are saying that our money losing Post Office makes money with Amazon. 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! — Donald J. Trump (@realDonaldTrump) April 2, 2018

Amazon shares were down more than 3.5% as the price of a single share slipped below the $1,400 level.

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President Trump's obsession and escalating feud with Jeff Bezos, and bringing Amazon to heel before it destroys what's left of America's crumbling brick-and-mortar retail industry, was on display Saturday morning when he fired off a series of angry tweets claiming the Bezos-owned Washington Post should register as a lobbyist and that the Post Office should jack up its parcel rates to stick it to Amazon.

"While we are on the subject, it is reported that the U.S. Post Office will lose $1.50 on average for each package it delivers for Amazon," Trump tweeted.

"That amounts to Billions of Dollars. The Failing N.Y. Times reports that 'the size of the company’s lobbying staff has ballooned,' and that does not include the Fake Washington Post, which is used as a 'lobbyist' and should so REGISTER. If the P.O. 'increased its parcel rates, Amazon’s shipping costs would rise by $2.6 Billion.' This Post Office scam must stop. Amazon must pay real costs (and taxes) now!"

While we are on the subject, it is reported that the U.S. Post Office will lose $1.50 on average for each package it delivers for Amazon. That amounts to Billions of Dollars. The Failing N.Y. Times reports that “the size of the company’s lobbying staff has ballooned,” and that... — Donald J. Trump (@realDonaldTrump) March 31, 2018

...does not include the Fake Washington Post, which is used as a “lobbyist” and should so REGISTER. If the P.O. “increased its parcel rates, Amazon’s shipping costs would rise by $2.6 Billion.” This Post Office scam must stop. Amazon must pay real costs (and taxes) now! — Donald J. Trump (@realDonaldTrump) March 31, 2018



Trump's latest salvo follows several attack tweets earlier this week, where Trump accused Amazon of paying "little or no taxes" while putting "thousands of retailers out of business."

His angry tweets have sent the company's shares plunging, extending a drop that began with an Axios report saying Trump is fixated on containing Amazon's inexorable expansion, potentially by invoking anti-trust measures and breaking down the company. In total, Amazon founder Jeff Bezos saw his net worth plunge by $13 billion during the selloff

I have stated my concerns with Amazon long before the Election. Unlike others, they pay little or no taxes to state & local governments, use our Postal System as their Delivery Boy (causing tremendous loss to the U.S.), and are putting many thousands of retailers out of business! — Donald J. Trump (@realDonaldTrump) March 29, 2018

As slumping Amazon shares weighed on the broader market last week, the White House clarified that the White House had no actions planned against Amazon.

"The president has expressed his concerns with Amazon," White House spokeswoman Lindsay Walters told the press pool on Air Force One. "We have no actions at this time."

As Politico points out, Trump's $1.50 number comes from a WSJ op-ed which cited a Citigroup analysis that the Postal Service loses about $1.46 for every package it delivers for Amazon. But part of this is due to a law that prevents the limits the chronically money-losing USPS ability to compete with for-profit private sector peers such as FedEx and UPS.