NEW YORK (

TheStreet

) -- Retailers are rallying ahead of the all-important Black Friday weekend.

The S&P Retail Index is gaining 1.7% to 492.48, led up by strong earnings results from

Tiffany

(TIF) - Get Report

and

Guess

(GES) - Get Report

.

Tiffany reported a 27% jump in third-quarter profit as sales rebounded, sending shares up 5% to $61.12 in morning trading. The high-end jeweler also upped its full-year guidance by 12 cents for the third time. It now expects 2010 earnings in the range of $2.72 to $2.77 a share.

Guess is surging 7.5% to $48.72, following its better-than-expected third-quarter earnings report. During the quarter the specialty apparel retailer earned $69.1 million, or 75 cents a share, compared with analysts' forecast of 59 cents. Revenue climbed 17% to $613.9 million.

Looking ahead, Guess foresees full-year earnings between $3.02 and $3.06 a share, better than the $2.91 a share Wall Street predicts. For the fourth quarter it is calling for earnings in the range of $1.02 to $1.06 a share, also higher than estimates of $1.02 a share.

Internet stocks

Amazon

(AMZN) - Get Report

and

eBay

(EBAY) - Get Report

are also on the rise, as online shopping is expected to gain a bigger slice of holiday sales this year.

Overall, e-commerce sales during the holiday season are expected to rise 10% to $32 billion, according to Susquehanna Financial.

Amazon is gaining 4% to $175 in morning trading, while eBay is increasing 2% to $30.75.

-- Written by Jeanine Poggi in New York.

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