(Thomson Reuters earnings article updated with corrected information on its professional and markets division revenue.)

NEW YORK ( TheStreet) -- Thomson Reuters ( TRI) saw earnings fall below expectations in the second quarter driven by low sales in 2009.

For the three months ended June 30, Thomson Reuters saw earnings fall 9.4% to $297 million, or 35 cents a share, compared with earnings of $325 million, or 38 cents a share, in the same period a year ago.

Revenue declined 2% to $3.22 billion from $3.29 billion during the quarter.

The company's markets division revenue dropped 4% from $1.9 million to $1.8 million and its professional division revenue grew 2% to $1.39 billion from $1.37 billion.

For the first half of the year, earnings fell 16.8% to $431 million for Thomson Reuters, or 59 cents a share, compared with earnings of $518 million, or 60 cents a share, in the same period a year ago.

Thomson Reuters plans to invest in new products such as WestlawNext, Thomson Reuters Eikon and the ONESOURCE global tax workstation. While Thomas Glocer, the CEO of Thomson Reuters, says these investments may "suppress margins by some 100 basis points in 2010," he added that these new products will help the company "drive growth, strengthen its competitive position and improve margins for years to come."

Thomson Reuters revenue dropped 1% from $6.36 billion from $6.42 billion. The company expects revenue to remain flat to slightly down in 2010 as a result of negative sales in 2009, but management remains positive.

"I am pleased with the continuing progress the company has made in the first half of the year," said Glocer. "While our markets are only slowly improving, we have seen accelerating results in terms of revenues, net sales and customer uptake of our new products."

Thomson Reuters shares have fallen since the Thursday opening bell, and 30 minutes into the day are down 1.4% to $37.69.

-- Reported by Theresa McCabe in Boston.

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