Wal-Mart

(WMT) - Get Report

, the world's biggest retailer, reported third-quarter earnings that topped analysts' expectations as sales rose 7.5% to $97.6 billion but trimmed its earnings forecast for the fiscal year.

Net income in the quarter was $3.1 billion, or 80 cents a share, compared with earnings of $2.9 billion, or 70 cents a share a year earlier. Earnings from continuing operations in the quarter were 77 cents a share. Analysts surveyed by

Thomson Reuters

expected earnings of 76 cents a share.

"Despite economic difficulties around the world, we achieved solid sales and earnings growth and we are optimistic about the upcoming holidays," said Lee Scott, president and CEO, in a statement Thursday.

Total comparable-store sales in the U.S. in the third quarter rose 3%, without fuel, the retailer said.

For the fourth quarter, Wal-Mart estimates a comparable-store sales increase in the U.S. of between 1% and 3%, and said it expects earnings from continuing operations of between $1.03 and $1.07 a share.

"The rapid changes in currency exchange rates during the last few weeks are projected to negatively affect this year's fourth-quarter results by approximately 6 cents per share," said Tom Schoewe, chief financial officer. He added that strong operating performance in the company's international operations may be overshadowed by the currency fluctuations.

Analysts expect fourth-quarter earnings of $1.11 a share.

Wal-Mart said it revised its earnings guidance for the full year ending Jan. 31, 2009, to $3.42 to $3.46 a share. The company previously expected fiscal-year earnings of $3.43 to $3.50 a share. Analysts expect earnings of $3.49 a share.