Whole Foods sinks after key metric misses

Whole Foods to open new chain of stores
Whole Foods to open new chain of stores

Grocery chain Whole Foods Market stock sank after a key sales metric missed estimates on Wednesday.

The grocer reported adjusted earnings of 43 cents a share, up from 38 cents per share in the year-ago quarter.

Revenue rose to $3.65 billion in revenue from $3.32 billion in the prior-year period. Comparable store sales rose 3.6 percent. Same-store sales were expected to jump 5.3 percent, according to a Consensus Metrix estimate.

Wall Street expected Whole Foods to deliver 43 cents in earnings per share on $3.71 billion in revenue, according to a consensus estimate from Thomson Reuters.

Following the report, the stock sank 10 percent. (Click here to track the company's shares following the report.)

Whole Foods EPS inline; light miss on revenue
Whole Foods EPS inline; light miss on revenue

Whole Foods is competing in an increasingly competitive market with mainstream grocers and discount grocers like Wal-Martexpanding their organic offerings.

Read MoreMicrolending gets anorganic boost from Whole Foods

In a release, the chain announced it is launching a new store concept with stores to begin opening next year.

"Offering our industry-leading standards at value prices, this new format will feature a modern, streamlined design, innovative technology and a curated selection. It will deliver a convenient, transparent, and values-oriented experience geared toward millennial shoppers, while appealing to anyone looking for high-quality fresh food at great prices," said said Walter Robb, co-chief executive officer of Whole Foods Market, in the release.

For the full fiscal year 2015, Whole Foods expects comparable store sales growth in the low to middle single digits.

Tune In: Whole Foods Co-CEO Walter Robb will be on CNBC "Squawk on the Street" at 9:35 a.m. Thursday.

Correction: This number has been updated to reflect the company's adjusted earnings for the quarter.