Shake Shack shaken up

Shake Shack

Shake Shack shares plunged by the most in four years

after the New York-based burger chain warned of

slower growth ahead.

Although its third-quarter results beat expectations,

- FWBP Digital Partners -

Shake Shack gave a modest growth outlook and management said it expects

a “lot of volatility” this year. The more-than 250-store chain is expanding both

within the U.S. and internationally, but it’s dealing with a number of changes, such as the closure of some of its stores for upgrades. It’s also grappling with higher product, labor and marketing costs. It’s recent decision to rely exclusively on Grubhub for its delivery operations is also weighing on Shake Shack’s sales, the company said.

Shares sank 21 percent Tuesday.