Net sales are an important metric for the division that serves the banking industry and one that Thomson Reuters has struggled to expand since Canada's Thomson Corp acquired Reuters Group Plc in 2008.

Overall, the company said third-quarter revenue increased 1 percent before currency changes to $3.1 billion on the strength of its Legal and Tax & Accounting businesses. Analysts on average were expecting $3.1 billion, according to Thomson Reuters I/B/E/S.

"It's another solid quarter of performance, and we are quite encouraged by what we are seeing," Chief Executive Officer Jim Smith said in an interview.

Smith also pointed to better trends at the Legal division, which includes products and services like WestlawNext and Practical Law. Revenue for that business increased 1 percent to $854 million, its first rise excluding acquisitions since the second quarter in 2013.

Tax & Accounting revenue rose 13 percent to $301 million.

Revenue at the Financial & Risk division fell 2 percent to $1.62 billion but should improve next year because it lags net sales by about three quarters.

Smith said the company expected a stronger revenue performance in 2015, but it was too early to say if net sales would be positive for the fourth quarter.

Europe, whose economic instability has caused banks to pull back on spending and slash costs, has been a particular challenge for Thomson Reuters. Smith said the environment had improved there, although professionals markets were "far from robust."

Thomson Reuters' net income attributable to common stockholders fell to $231 million, or 28 cents a share, from $271 million, or 33 cents a share, a year earlier.

Excluding items like tax charges, earnings of 45 cents per share were in line with analysts' estimates.

The company affirmed its outlook for the year and expects revenue to be unchanged from last year's $12.5 billion.

In early trading, shares of Thomson Reuters were down 0.4 percent on the Toronto and New York stock exchanges.

(Reporting by Jennifer Saba in New York; Editing by Lisa Von Ahn)

By Jennifer Saba