Shares of Amazon.com Inc. AMZN, -3.60% slumped 3.3% in afternoon trading Wednesday, putting them on track to close at a more-than two-year low. The ecommerce and cloud services behemoth's stock, which is headed for the lowest close since April 9, 2020, has now tumbled 27.2% since first-quarter result were reported after the April 28 close, wiping out about $400.05 billion in market capitalization since then.