UPDATE 1-FactSet Q3 EPS beats Street by a penny

* Q3 EPS $0.78 vs est. $0.77

* Q3 rev rose 4 pct, in-line with est

* Sees Q4 rev $165-169 mln vs est. $162.6 mln

* Sees Q4 EPS $0.78-$0.80

June 15 (Reuters) - FactSet Research Systems Inc (FDS.N) posted a quarterly profit that marginally beat Wall Street expectations and gave a strong fourth-quarter revenue forecast, saying the health of its clients has started to improve.

The financial information services provider posted net income of $38.7 million, or 81 cents a share, compared to $38.5 million, or 79 cents a share in the year-ago period. The latest third-quarter results includes a tax benefit of 3 cents a share.

Analysts were expecting a profit of 77 cents a share, according to Thomson Reuters I/B/E/S.

Revenue for the quarter ended May 31 rose 4 percent to $160.3 million, in-line with analysts' average estimate. The company said its operating margins expanded 20 basis points to 34.7 percent.

For the fourth quarter, the company said it expects revenue of $165 million to $169 million and earnings per share of 78 cents to 80 cents. Both ends of the profit range include a 1 cent reduction to reflect the lapse of the U.S. Federal R&D tax credit effective Dec 31, 2009.

Analysts were expecting a profit of 78 cents a share on revenue $162.6 million.

Shares of FactSet Research closed at $69.08 Monday on the New York Stock Exchange. (Reporting by Jennifer Robin Raj in Bangalore; Editing by Aradhana Aravindan)