(Reuters) - Technology stocks led the S&P 500 and Nasdaq to record closing highs on Friday, with the S&P ending above 2,600 points for the first time, while Amazon and retail stocks got a boost from signs of a strong start to the holiday shopping season.

The benchmark S&P 500 and the blue-chip Dow Jones industrials posted weekly gains for the first time in three weeks while the Nasdaq Composite posted its best weekly performance since the week to Sept. 1.

The stock market had a half session on what is known as Black Friday, the day after the Thanksgiving holiday and the unofficial start of the U.S. holiday shopping season.

U.S. stores offered deep discounts, entertainment and gifts to draw bargain hunters, but some shoppers said they were just eyeing goods, reserving their cash for online purchases.

On Thursday, Thanksgiving Day, U.S. shoppers spent more than $2.87 billion online, according to Adobe Analytics.

Adobe, which measures 80 percent of online transactions at the largest 100 U.S. web retailers, forecast online Black Friday sales of $5 billion, which would be a record high. Online retailers could rake in an additional $6.6 billion on Cyber Monday.

The S&P retail index .SPXRT rose 0.75 percent and hit a record intraday high, led by Amazon's AMZN.O 2.6 percent gain.

“In the retail environment, Amazon is extremely important - the fact that Amazon continued to soar bodes well for the fourth-quarter holiday shopping season and it bodes well for Wall Street,” said Adam Sarhan, chief executive of 50 Park Investments.

Brick-and-mortar stores, which have been boosting their online presence, also fared well.

Traders work on the floor of the New York Stock Exchange (NYSE) in New York, U.S., November 20, 2017. REUTERS/Brendan McDermid

Macy's M.N closed up 2.1 percent at $21.07. The department store operator's chief executive told CNBC the company was better off this year than last and was seeing very robust online demand.

Kohl's KSS.N, Gap GPS.N and J.C. Penney JCP.N were up between 0.6 percent and 1.6 percent.

Target TGT.N ended 2.8 percent lower at $55.88, with analysts noting that it closed its stores for several hours overnight while rivals stayed open. Wal-Mart WMT.N inched up 0.2 percent.

The Dow .DJI rose 31.81 points, or 0.14 percent, to 23,557.99, while the S&P .SPX gained 5.34 points, or 0.21 percent, to 2,602.42. The Nasdaq .IXIC added 21.80 points, or 0.32 percent, to 6,889.16.

The CBOE Volatility Index .VIX, better known as the VIX and the most widely followed barometer of expected near-term stock market volatility, closed at 9.67, nearly a three-week low. Just after the stock market closed at 1 p.m. New York time (1800 GMT), the VIX fell to 8.56, ostensibly a record intra-day low. A CBOE Global Markets spokeswoman, however, said it was not a 'legitimate quote' and was caused by S&P 500 options quotes briefly going wide in thin, low volume markets. It was not immediately clear whether the CBOE would update historical data for the VIX to correct the quote.

The energy index .SPNY and the materials index .SPLRCM were boosted by rising commodities prices.

U.S. oil prices CLc1 jumped to a more than two-year high as North American markets tightened on the partial closure of a key pipeline linking Canada and the United States. [O/R]

About 2.78 billion shares changed hands in U.S. exchanges in the shortened session. The daily average over the last 20 full sessions is 6.48 billion shares. Last year, volume during the session after Thanksgiving was 3 billion shares.

Advancing issues outnumbered declining ones on the NYSE by a 1.61-to-1 ratio; on Nasdaq, a 1.31-to-1 ratio favored advancers.

The S&P posted 35 new 52-week highs and one new low; the Nasdaq recorded 120 new highs and 21 new lows.

For a graphic on S&P 500 hundred-level milestone record highs during current bull market, click reut.rs/2AuuRzh