Monday has been another sad day for the U.S. newspaper industry, while shares of four companies hit all-time lows, Editor & Publisher reported.

The drops were led by GateHouse Media Inc., with a 21 percent plunge in shares to 66 cents a share. Others included McClatchy Co., Lee Enterprises, and Sun-Times Media Group.

GateHouse's shares have been down in the past three weeks, but so far there is no explanation for the sell-off. It closed at 66 cents, down 18 cents, or 21.43 percent. According to E&P, its floor trading has been suspended, and the stock may be de-listed from the New York Stock Exchange.

Lee Enterprises closed at US$2.90, which dropped 22 cents, or 7.05 percent, from its opening. It had traded during the last 52 weeks at the highest of $20.60.

The McClatchy Co. ended at $4.25 Monday, down 15 cents, or 3.41 percent. During the past year, it has traded as high as $26.43.

In Addition, the Sun-Times Media Group closed at 26 cents a share, E&P reported.

Other companies losing shares Monday include Gannett Co. Inc., Media General Inc., The New York Times Co., Journal Communications, Inc., E.W. Scripps Co. and Journal Register Co., E&P reported.