Shake Shack CEO: Our growth is just getting started

• Shake Shack's stock may be down from its highs but CEO Randy Garutti isn't concerned, telling CNBC the burger chain's growth "is a "long-run story."
• He feels like the company is just getting started, and envisions 450 stores in the U.S. alone.
• "We've hit on something. We've hit on a moment in the world," he said.

Shake Shack's stock may be down significantly from its highs but CEO Randy Garutti isn't concerned, telling CNBC the burger chain's growth "is a "long-run story."

Shares of Shake Shack are up 16 percent in the last three months, but are down 17 percent since the company's initial public offering in January 2015. After a big runup, the stock is now down about 50 percent from its highs two years ago.

"We feel like every day we're barely getting started," Garutti said in an interview with "Power Lunch" on Wednesday.

"We're having a lot of fun … just building a company for decades to come."

In fact, the chain has just reached 134 stores across the globe, up from around 60 when it went public.

And Garutti envisions at least 450 Shake Shacks in the U.S. alone.

"We've hit on something. We've hit on a moment in the world. People want to know where their food comes from. They want to know it's with great ingredients served by really sincere, hospitable people," said Garutti, who is author of the new book, "Shake Shack: Recipes and Stories."

He pointed to the chain's "rabid fans" and the fact that the stores have been successful across the country.

"That's what people who are buying the stock and holding it and believing in this story for the long term understand. This is a story of unit growth. This is a story of absolutely huge sales growth opportunity and a story of people who have just become serious fans of loving what we do."

Piper Jaffray appears to agree with Garutti's assessment. In May, the firm initiated coverage on the stock, with analyst Nicole Miller Regan saying Shake Shack presents a highly compelling, growth-restaurant investment opportunity.

"With the company's culture of operational excellence we believe the brand is favorably positioned to double its unit base during the next five-year period," she wrote in a note to clients.

Regan started her price target for Shake Shack at $44.

— CNBC's Tae Kim contributed to this report.