Shares of Tiffany & Co. jumped Friday after the global jewelry retailer reported net earnings for the three months ended in July higher by 33 percent and it raised its full-year outlook.

Shares of the global retailer up $3.78, or 5.53 percent, in premarket trading to $66.56, near its 52-week high.

Net earnings for the three months ended July 31 rose a third to $90 million, or 69 cents per diluted share, compared to $67.7 million, or 53 cents per diluted share in the year-earlier quarter. Excluding one-time events, the company's net earnings for its second quarter climbed 58 percent.

Global sales for the three months in Tiffany's 236 stores rose 30 percent to $872.7 million.

The company increased its full-year earnings forecast to $3.65 to $3.75 per diluted share, not including nonrecurring expenses, from the previous forecast of $3.45 to $3.55 per diluted share on better-than-expected second quarter results.

Tiffany repurchased about 330,000 shares of its common stock in the second quarter at a total cost of $24.5 million, or an average cost of $74.29 per share. In the first half, the company spent $52.5 million to repurchase about 783,000 shares at an average cost of $67 per share. As of July 31, about $340 million remained available for future repurchases under a plan that expires January 2013.