Donald Trump has turned his fire on Amazon with a series of complaints about the online retailer's tax practices and the threat it poses to smaller rivals.
Shares in the tech giant fell by more than 4% on Thursday after Mr Trump set out the gripes in a tweet though they later recovered to end 1% higher after the White House said "no actions" were currently planned against the company despite the concerns.
The President's comments had appeared to add weight to a report a day earlier that Mr Trump wanted to "go after" the company.
That report had sent Amazon's shares 4% lower on Wednesday, wiping around $30bn off its market value.
In his tweet on Thursday, the President said that unlike others, Amazon paid "little or no taxes" to state and local governments, and that it was "putting many thousands of retailers out of business".
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
News website Axios had reported on Wednesday that Mr Trump is obsessed with the retail giant and wants to rein in its power. It followed criticism of Amazon by the President in the past over taxes and jobs.
The report said Mr Trump had talked of using antitrust law to "go after" the company because he was worried about small family stores going under.
It also said that he wanted to change Amazon's tax treatment – an issue he raised publicly last year when he called for an internet tax for online retailers, though Amazon already collects sales tax on items it sells direct to customers.
White House spokeswoman Lindsay Walters said on Thursday: "The President has expressed his concerns with Amazon. We have no actions at this time."
Amazon founder and chief executive Jeff Bezos also owns the Washington Post, which Mr Trump has criticised as "fake news".
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The newspaper last year won a Pulitzer prize for an investigation into the President's donations to charities, which found that many of his philanthropic claims were exaggerated.
Amazon is the latest major US tech stock to come under pressure after Facebook acknowledged earlier this month that millions of users' data had been improperly harvested by consultancy Cambridge Analytica.