Thomson Reuters Corp reported a lower quarterly profit and said it expects 2010 revenue to be flat or to fall slightly because of the impact of negative net sales last year.

Fourth-quarter underlying profit fell 16 percent to $661 million. Adjusted earnings per share came to 44 cents, compared with 50 cents a year earlier, and a cent above the average Wall Street estimate, according to Thomson Reuters I/B/E/S.

Underlying operating profit margin fell to 19.7 percent from 23.7 percent last year.

Revenue from ongoing businesses, rose 1 percent to $3.35 billion, versus the average analyst forecast of $3.32 billion.

Excluding the impact of foreign exchange rates, revenue fell 3 percent.

Given our improving sales figures, I am confident that 2009 was the bottom of the sales cycle for us and that 2010 will see the corresponding bottom in period-on-period reported revenues, said Chief Executive Thomas Glocer in a statement.

I expect that we will return to revenue growth in the second half of 2010, he said.

Revenue in the Markets division, which provides news and data to financial industry customers and competes with companies such as Bloomberg LP and Rupert Murdoch's News Corp , fell 5 percent, not including the impact of foreign exchange rates.

Revenue in the Professional division, which sells databases and other information reservoirs to lawyers, accountants, scientists and healthcare workers, rose 1 percent, excluding the impact of foreign exchange rates.

(Reporting by Robert MacMillan; Editing by Ted Kerr.)