San Francisco may become the largest U.S. city to lose its main daily newspaper after Hearst Corp. threatened to sell or close the Chronicle unless it can push through more job cuts.

The publisher, already trying to sell the Seattle Post- Intelligencer, said yesterday that it would seek voluntary buyouts for a “significant” number of its 1,500 employees after the San Francisco Chronicle lost $50 million last year. The announcement follows two newspaper owners filing for bankruptcy protection since Feb. 21.