Following a less-than-savory second-quarter earnings report, shares of Whole Foods Market (WFM) were down by almost 19 percent on Wednesday.

CEO John Mackey had named the growing competition in the organic food market as a key reason for the retailer losing command of the market. "The growing demand for fresh healthy foods, the offering of natural and organic products is expanding everywhere and new stores, existing stores and online," he said on the firm's Q1 earnings call.

In its Q2 earnings report, the retailer revealed earnings of $0.38 per share, according to Business Insider. This was short of the $0.41 per share originally predicted for the period. Comp sales increased by 4.5 percent, falling short of a forecasted increase of 5.4 percent.

The retailer also decreased its predictions for the fiscal year, lowering 2014 sales from 11 percent to 10.5 percent.

"As we continue to innovate and evolve at a fast pace, we are confident in our ability to gain market share and expect our sales to approach $25 billion over the next five years," said Mackey in a press release. But many aren’t convinced that the low performance was fully the result of increased competition. "I’ve got to be honest. I’m not really hearing anything that’s suggesting management is taking this situation as seriously as some investors want you to," Ken Goldman at JPMorgan said. "There’s a lot of talk about what’s going, not a lot to talk about what it takes to win the change market."