San Francisco may become the largest U.S. city to lose its main daily newspaper, the Chronicle, after publisher Hearst Corp. said it would sell or close the newspaper unless it finds enough takers for staff buyouts, Bloomberg reported Wednesday.

Hearst spokesman Paul Luthringer, announced on Tuesday the 145-year-old Chronicle, which lost US$50 million last year, is looking for a "significant" number of its 1,500 staff at the San Francisco Chronicle to take buyouts. The publisher has already put the Seattle Post-Intelligencer up for sale.

As the 14th largest U.S. city, with a population of 744,000 according to the U.S. Census Bureau, the Chronicle's closure would mark the most significant impact of the global recession on the U.S. newspaper industry.

"The Chronicle plays an important role in our civic life and we don't want to see this treasured institution close its doors," San Francisco Mayor Gavin Newsom said in a statement, Bloomberg reported.

The potential closure of the Chronicle comes on the back of a number sales, job losses and bankruptcies around the industry with print advertising income at its lowest levels in at least 37 years, according to Newspaper Association of America Newspapers via Bloomberg.