DENVER — High Bluff Capital Partners, a San Diego-based private investment firm, has acquired quick-service sandwich chain Quiznos from QCE L.L.C. Financial terms of the transaction were not disclosed.

High Bluff Capital Partners specializes in turning around struggling consumer-facing companies across the restaurant, entertainment, food, beverage and retail markets, the company said. In the past, High Bluff has worked with Frito-Lay, Dairy Queen and AMC Theaters.

Quiznos operated around 5,000 units in 2007 before the chain filed for Chapter 11 protection in 2014. That year, the brand shuttered more than 400 stores. In 2017, Quiznos closed more than 100 units, and now the brand operates fewer than 800 locations in 32 countries – including about 400 U.S. units. Quiznos’ 2017 systemwide sales fell 21.7% to $172.4 million, according to Technomic’s Top 500 chain data.

“Quiznos is an iconic brand with strong awareness and attractive upside in the sandwich segment,” said Gerry Lopez, operating partner for High Bluff Capital Partners. “We are excited about the acquisition. We have the commitment, industry knowledge and flexible capital to build on recent successes and drive future, sustainable growth.”

Mr. Lopez will be the executive chairman of the new company that will operate the Quiznos brand. Susan Lintonsmith, president and chief executive officer of Quiznos since 2016, will continue in her role under High Bluff’s ownership.

“I’m proud of the progress we’ve made in the past few years,” Ms. Lintonsmith said. “I’m excited about the future with High Bluff Capital Partners and the level of experience and commitment they bring to Quiznos. I believe this is the infusion we need to take the brand to the next level.”