Amazon is currently the reigning champion of e-commerce in America, and President Donald Trump thinks that it should be paying the United States Postal Service more for its shipping services. Trump's argument is that USPS is losing money on Amazon delivery contracts by charging too low a rate. Amazon uses a number of different delivery services providers in the United States, with the Postal Service, Fedex, and UPS being the most prominent. While Trump's argument seems fairly cut and dry, there are multiple factors to consider, along with the fact that third parties can become involved; some shipping providers actually get parcels from local fulfillment centers and other destinations to the local post office, then let the Postal Service finish the delivery to the individual.
For what it's worth, the Postal Service is hiking up rates on premium stamps by 2% going forward, on the back of an order signed earlier in December. This means higher shipping rates, just as Trump has called for, though the dramatic wording in his Tweet suggests that he is calling for a far more drastic rate increase to stem the Postal Service's revenue bleed, which has continued for 11 years now, and has culminated in a figure of $2.7 billion in total net loss for this year. It bears mentioning that the Postal Service itself has said that these losses are largely due to change in interest rates that are beyond its control.
Trump has been attacking Amazon since before he became President, but his latest series of public condemnations against the company and its CEO cut to the core of the argument that e-commerce is encroaching upon traditional retail and other long-established tenets of the American economy. Though his supporters and dissidents fight it out so vehemently on each Tweet's comment thread that it's hard to find a consensus, the stock market was able to provide one, with Amazon stock temporarily taking a 1.4% nosedive, though it still beat figures for the same time last year, ending the day on a 55% net increase in share price for the year to date. This battle is likely far from over, but thus far, Amazon and CEO Jeff Bezos have not fired back, and neither Amazon nor the US government has made any official comment on this situation.