It's an "opening salvo" in the grocery wars, said Neil Saunders, managing director of GlobalData Retail, and shares of other supermarkets fell on the news.
"Rivals should be under no illusion that they are now dealing with a competitor that is not afraid to damage profits and margins if it creates long-term gains", Saunders said in an analyst note.
Another customer noted that Amazon products like Echos and Dots are now being sold at a discount in the middle of Whole Foods' produce section. So while Amazon can cut prices at Whole Foods to bring in more customers, Amazon will have to figure out how to reduce the rising cost of the products Whole Foods sells.
"All the signs in the store are saying, 'Look what Amazon's doing for you, '" said Stephen Beck, who owns a management consulting firm in NY.
In its announcement of the plan last week, Amazon described its "vision" to make the store "affordable for everyone". The stock edged up to $41.98 on Thursday.
The companies signaled last week that they would selectively cut Whole Foods prices starting on Monday, with further discounts in the works.
According to industry research, the largest barrier to Whole Foods' customers was price.
"We feel great about out position with our network of stores around the country and fast-growing e-commerce and online grocery business", a Wal-Mart spokesman said.
The FTC filed suit to unwind the deal, arguing that P&G would drive competitors from the market, not because those competitors offered an inferior product - all bleach is chemically identical - but because P&G had a promotional advantage. On Monday, the tab was $75.75, a 23 percent reductions.
"Half of Amazon's strategy is to cause a disruption, make other retailers go out and make a mistake because they're just trying to impress shareholders and get in the paper", Livingston added.
"We're really expecting great things", said Gandhi, who closely tracks grocery prices for her business selling prepared organic meals.
Concerns over their readiness to withstand Amazon's advance have weighed on Kroger and Target shares since Amazon said it was buying Whole Foods in June. "This shows that Amazon is taking a very hands-on approach". Some of the steepest price cuts were on meat: Fresh Atlantic salmon dropped by a third from$15 to $10 a pound, and Hass avocados by almost half.
On top of that, Amazon has already an global name for itself.
Shares of Kroger were down 0.7% in morning trades Monday.
Jeff Bezos is a traitor and a detriment to the USA.