Granite City Food & Brewery Ltd. says it has hired an investment banking firm to help the company with “a possible strategic transaction.”

The casual-dining restaurant group said its multiple options “may take the form of a sale, disposition, merger or other transaction involving all or a substantial portion” of the business.

The St. Louis Park company said its unaudited financial results showed revenues were $136 million in 2014, up from $134 million the previous year. It lost $2.5 million in 2014, the company said.

The restaurant-and-brewery chain has 31 locations, mostly in the Midwest, including five locations in Minnesota: Roseville, Eagan, St. Louis Park, Maple Grove and St. Cloud.

The concept was created in St. Cloud in 1999, and draws its name from that community’s history of granite mining.

The company also operates five restaurants under the name Cadillac Ranch All-American Bar and Grill, including one location at Mall of America.