For years, hedge funds marked the date of the organic grocer's earnings announcement on their calendars. Its quarterly results provided a rare window into the burgeoning market for organic food and how upscale Americans ate and shopped. And everyone, whether bull or bear, had an opinion.

Those days are gone. Since last August, when Whole Foods was swallowed up by Amazon.com, there's been a virtual blackout. The grocery chain is now little more than a footnote in the e-commerce behemoth's earnings statements. Barely a peep comes out of analyst calls.

"It's not the same," said Jennifer Bartashus, a retail-staples analyst at Bloomberg Intelligence. Before, "you could see the whole dynamic playing out. There's no equivalent in the public space right now."