Shake Shack's shares hit new high as speculation swirls over "Chicken Shack" filing

Shake Shack's shares surged to another record high Friday, fueled in part by speculation that the hamburger chain could be thinking about dishing out chicken.

Last month, a unit apparently tied to Shake Shack's parent company applied to trademark the words "Chicken Shack" for chicken sandwiches. The company has yet to offer more details, but its stock has soared 33 percent this week.

Shake Shack's market value has more than quadrupled since its initial public offering in January.

Earlier this month, Shake Shack Inc. reported first-quarter earnings that topped Wall Street's expectations, thanks to a 56 percent increase in sales. The New York company also increased its revenue outlook for the year to between $161 million and $165 million, up from a range of $159 million to $163 million.

Over recent years, the company has expanded its burger stands from the middle of Manhattan to Las Vegas and other spots around the country, then opened stands in Moscow, Dubai and other cities around the world. As of April 1, Shake Shack had 66 stores, 39 of them in the U.S. It has opened two more stores since then and plans to add at least 10 more in 2015.

Its original location, an outdoor stand in the middle of Manhattan's Madison Square Park, reopened for the season Wednesday.

Shares in Shake Shack were up $3.23, or 4 percent, to $93.10 on Friday. They hit an all-time high of $96.75 in the first few minutes of trading.