Some of America's largest and most storied metropolitan newspapers are up for sale, in a sign of the turmoil facing an industry struggling to find a business model in the digital age.

The Boston Globe recently went on the market as its parent company, The New York Times Co., said it was exploring options for the daily. The Los Angeles Times, Chicago Tribune and Baltimore Sun are also on the auction block, along with five others owned by parent Tribune Co., which is refocusing after bankruptcy.

The shakeup in newspapers, which follows changes in ownership at several other large US dailies, portends dramatic changes in a key US media segment.

But the desire to sell is motivated by factors other than cashing out, given the grim reality that newspaper companies no longer attract a litany of buyers or the hefty prices they once fetched.

Despite their legendary status, they are worth only about a tenth of the value from their heyday of a decade or two earlier, said Ken Doctor, a media analyst at the research firm Outsell.

"These are the papers which broke national stories," he said. "They have been important -- and they have been the ones hardest hit by all the changes and digital disruption." The Boston Globe, which was acquired by The New York Times Co. in 1993 for USD 1.1 billion, "will sell for around USD 110 million today."