Reuters: Amazon.com Inc’s. shares fell almost 5 percent today, wiping more than $30 billion off its market value, after news website Axios reported that President Donald Trump is obsessed with the world’s largest online retailer and wants to rein in its growing power. Trump has talked about using antitrust law to “go after” the company because he is worried about mom-and-pop retailers being put out of business by Amazon, Axios reported.