New York Times Co. is formally exploring a sale of the Boston Globe, its only remaining business outside the core New York Times media brand.

The publisher is working with Evercore Partners Inc. as an adviser for a sale, Times Co. said today in a statement. The company intends to focus its strategy and investment on the Times brand, it said.

Times Co., controlled by the Ochs-Sulzberger family, is coping with a difficult advertising market as spending on national campaigns continues to shrink industrywide. The publisher has sold other assets unrelated to the Times brand, getting rid of regional newspapers and About.com within the past 13 months.

The company held $955 million in cash and short-term investments at the end of last year, largely as a result of its asset sales. In addition to the Boston Globe, the company still owns the International Herald Tribune, considered the European edition of the New York Times.