On Wednesday, the Axios news website carried a story claiming that US President Donald Trump was "'obsessed" with online retailer Amazon and wants to "go after" the company.

President Trump responded to the article on Twitter. He didn't deny that he has a problem with Amazon, quite the opposite.

He confirmed that he's had concerns about the company for some time. He accused Amazon of not paying enough taxes, using the US Postal Service as its 'delivery boy' and putting 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

In a week when Facebook was the focus of much criticism amid data security concerns, it was another internet giant that felt the full force of the President's ire.

So what has led to this dislike of Amazon? Are packages to the White House not being delivered on time? Or is it something to do with the CEO and founder of Amazon, billionaire Jeff Bezos?

According to Axios, Mr Trump has discussed changing Amazon's tax treatment and has wondered aloud if it might be possible to take a case against Amazon under competition law.

The report claims that the president's wealthy, real estate friends are telling him that Amazon is killing traditional shopping malls and high street retailers.

Following the release of the article, the White House was asked if there is a plan to target Amazon but Press Secretary Sarah Sanders said no said specific policies were currently being considered.

"The president has said many times before he is always looking to create a level playing field for all businesses, and this is no different," she added.

The clarification, however, wasn't enough to reassure Amazon investors. The company's share price fell following the Axios report and dipped again a day later following Donald Trump's tweet.

It wasn't the first time Donald Trump has taken to Twitter to criticise the online retailer.

Amazon is doing great damage to tax paying retailers. Towns, cities and states throughout the U.S. are being hurt - many jobs being lost! — Donald J. Trump (@realDonaldTrump) August 16, 2017

So let's look at President Trump's criticisms of Amazon. First, the allegation that the company doesn't pay its fair share of taxes.

In Ireland, we're used to hearing claims of tech firms and multinationals not paying enough tax and it's a debate that rages here in the US as well.

The White House is looking at the idea of an internet sales tax. There are also calls for e-commerce companies to collect state sales taxes but this is something Amazon already does.

What about Donald Trump's claim that Amazon is a burden on the US postal system? There is an argument that the rise of Amazon has actually benefitted the postal service.

Revenues from parcel deliveries are up but it hasn't been enough to offset the sharp decline in letter revenue, which has been a big problem for the postal service since the rise of email and online billing.

It's true that traditional, high street retailers are suffering in the age of online shopping, but Amazon alone cannot be blamed for this. Internet shoppers have countless websites to choose from.

There is a school of thought that Donald Trump's dislike of Amazon might be personal rather than business.

The company's CEO and founder, Jeff Bezos, is now the world's richest man. Forbes gives him the top spot on its rich list with an estimated fortune of $120bn. Donald Trump has a lower ranking with a net worth, according to Forbes, of $3bn.

If this is a personal grudge, however, it probably goes much deeper than rich list envy. Jeff Bezos also owns the Washington Post, a paper that Donald Trump does not like. Its journalists frequently break stories that are critical of the White House.

In July last year, Donald Trump tweeted that many articles about him in the Post were "fake news" and in another tweet he asked if the Washington Post was being used as a "lobbyist weapon" against Congress.

Is Fake News Washington Post being used as a lobbyist weapon against Congress to keep Politicians from looking into Amazon no-tax monopoly? — Donald J. Trump (@realDonaldTrump) July 25, 2017

People use Amazon for everything from washing powder to furniture and many items are delivered on the same day, hours after the order is placed.

Amazon is only set to get bigger as it moves into the grocery market. Last year, the company bought the Whole Foods supermarket chain for almost $14 billion.

Donald Trump has embraced technology when it comes to Twitter and is a master at using it to spread his message. The site allows him to bypass the traditional media and effectively "cut out the middleman".

Amazon does the same by bypassing traditional retailers, getting products straight to customers’ homes and "cutting out the middleman".

Given that they follow the same model one would think Donald Trump would have more respect for Amazon but he's clearly not a fan.