Earlier this year, Amazon unveiled a prototype for a physical food retailer called Amazon Go that will operate without checkout lines.
"The ramifications for all of retail are seismic - not just retailers that sell grocery, but for everyone", Gordon Haskett analyst Chuck Grom said.
In the United Kingdom, where there are Whole Foods stores, sell-offs wiped out almost $2billion (£1.5billion) from the value of stocks at grocers Tesco, Sainsbury's and Marks & Spencer, according to This Is Money.
Wal-Mart's stocks fell 4.7 percent when the deal was announced. The deal is estimated to be worth almost $13.7 billion, at $42 per share.
Amazon has agreed to pay $42 per share in cash for Whole Foods, a 27 percent premium on its closing share price on Thursday. Amazon also offers grocery shipments elsewhere, but that's tough with perishable foods. Her daughter Bethany Capels agrees and says she likes Whole Foods for the organic fruits she can serve her kids.
Amazon (AMZN) stock also jumped 2.44 percent to $987.71 on Friday on traded volume of 11.47 million shares versus average volume of 3.74 million shares. Certainly, it would appear to Cantillon that Bezos sees the future as slightly more nuanced than the vista of couch-bound online shoppers ordering everything from fast food to films online. Amazon also wants fewer employees in each store, with those who remain providing product expertise, rather than performing mundane tasks.
And while some analysts expect Amazon to bring vast buying power to Whole Foods, Amazon's heft in the food market is far smaller than in other areas, and high demand for organic products gives farmers unusual bargaining power. That prodding irked Mackey, who has referred to Whole Foods as his "baby" and to Jana as "greedy bastards".
"The entry of the king of web retail into the food space has to rattle the other companies", said Brad McMillan, chief investment officer at Commonwealth Financial Network.
Amazon already offers grocery-delivery services in five markets, but the Whole Foods purchase would let it expand to many more.
Whole Foods had fiscal 2016 sales of about $16 billion.
Jana, which disclosed an 8.3 percent stake in Whole Foods in April and is the company's second biggest shareholder, stands to make roughly $300 million from the sale to Amazon. According to data from market researcher NPD Group, 24 percent of young shoppers bought at least one item from Whole Foods previous year, compared with 20 percent of all consumers, a penetration rate the market researcher says is extraordinary for a chain of its size. Selling produce online is hard. The Whole Foods purchase may help it resolve that issue.
Adrienne Anderson, at a Whole Foods in Savannah, Georgia, says she shops at Whole Foods nearly exclusively for meat and fresh produce "because of the quality and selection" and because fruits and vegetables are locally sourced.
With this strategy, Amazon is planning to make the prices competitive and attract "more low- and middle-income shoppers" to its retail stores, which may still be located in posh localities.