Following up on last week's story that sent grocery - and Wal-mart - stocks tumbling, when Amazon announced it would cut Whole Foods prices as soon as Monday, Bloomberg reports that according to channel checks, "Amazon spent its first day as the owner of a brick-and-mortar grocery chain cutting prices at Whole Foods Market" by as much as 43%.

Some early examples observed at the Whole Foods store on 57th Street in Manhattan:

• organic fuji apples were marked down to $1.99 a pound from $3.49 a pound;
• organic avocados went to $1.99 each from $2.79;
• organic rotisserie chicken fell to $9.99 each from $13.99;
• banana prices were slashed to 49 cents per pound from 79 cents.

Following the news, European grocery stocks ticked lower again, while Kroger was down 2%, as apparently the size of the markdowns came as a surprise to the market and as Whole Foods peers will now struggle to catch down to its heavily subsidized competitor, watching their margins and profitability erode in the process.