NEW YORK (Reuters) - Four of the largest newspaper companies in the United States are teaming up to create an online advertising sales network focused on premium advertisers seeking a national audiences.

New York Times Co , USA Today publisher Gannett Co , Los Angeles Times publisher Tribune Co and San Francisco Chronicle publisher Hearst Corp have set up a stand-alone company called quadrantOne to oversee the aggregation of audiences.

The new network would be the second online partnership among newspapers in recent years. Some other publishers already have a partnership with Yahoo Inc .

QuadrantOne said its network would have a reach of nearly 50 million monthly unique visitors, based on Nielsen Online figures from December, and cover 27 out of the top 30 markets.

The company said the network would be open to any affiliate companies in addition to the four owner companies.

"Each participating company has agreed to dedicate advertising inventory to quadrantOne, so the network can offer customized online campaigns on a highly competitive basis," interim Chief Executive Dana Hayes said in a statement.

(Reporting by Yinka Adegoke; Editing by Lisa Von Ahn)
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