(c) 2013, Bloomberg News.

(c) 2013, Bloomberg News.

NEW YORK U.S. stocks fell Friday as investors sold shares in the final half hour of a shortened trading session, erasing earlier gains fueled by a rally in online retailers amid Black Friday sales.

Archer-Daniels-Midland fell 3 percent after Australia blocked a A$2.2 billion ($2 billion) takeover of GrainCorp. EBay and Amazon.com gained at least 1.8 percent. Best Buy and Coach advanced more than 1.4 percent as retailers opened their doors to holiday shoppers. Apple rose 1.9 percent after a report showed the company sold three of every four smartphones in Japan last month.

The S&P 500 fell 0.1 percent to 1,805.81, reversing an earlier gain of as much as 0.4 percent. The gauge advanced 0.1 percent for the week, extending its winning streak to eight weeks, the longest since 2004. The Dow Jones industrial average lost 10.92 points, or 0.1 percent, to 16,086.41. Trading in S&P 500 stocks was 8.9 percent below the 30-day average. U.S. markets were closed Thursday for the Thanksgiving holiday and Friday's trading ended at 1 p.m. EDT.

"It's very light trading," John Manley, who helps oversee $233.6 billion as chief equity strategist for Wells Fargo Funds Management in New York, said in a phone interview. The Friday after Thanksgiving is "going to be subject to light volume."

The S&P 500 rose 2.8 percent for the month. The benchmark gauge has climbed 27 percent in 2013, poised for its best year since 1998, and the Dow has gained 23 percent after the Federal Reserve refrained from tapering its third round of economic stimulus.

Investors are awaiting reports on manufacturing and home sales next week, and the November release of non-farm payrolls on Dec. 6. Janet Yellen, who will replace Ben Bernanke as chairman of the Fed, has said she will ensure monetary stimulus isn't removed too soon to support economic recovery in the U.S.

A report Friday showed euro-area unemployment unexpectedly declined in October, the latest indication that the bloc's recovery is gaining traction. Separate data Thursday showed economic confidence in the euro region improved more than economists forecast to a 27-month high in November.

The Chicago Board Options Exchange Volatility Index rose 5.5 percent Friday to 13.7. The gauge of S&P 500 options known as the VIX declined 0.4 percent for November.

Eight of 10 main industry groups in the S&P 500 slid Friday, with telephone stocks falling the most. Airlines lost 1.2 percent as a group. Southwest Airlines fell 1.9 percent to $18.59 and US Airways Group sunk 2.1 percent to $23.48.

ADM dropped 3 percent to $40.25. Australia's rejection of the agricultural commodities producer's takeover prompted a record 22 percent drop in GrainCorp, the biggest crop handler on Australia's east coast, and a slide in the local currency.

Technology companies gained 0.5 percent, the most among S&P 500 groups. EBay rose 2.5 percent to $50.52 and Amazon.com jumped 1.8 percent to $393.62. Online sales are projected to climb as much as 15 percent to $82 billion during the holidays, more than three times faster than the total gain of 3.9 percent to $602.1 billion, according to the National Retail Federation.

Apple rose 1.9 percent to $556.07. The company accounted for 76 percent of smartphone sales in Japan last month after the country's largest carrier, NTT Docomo, began offering the iPhone, market researcher Kantar Worldpanel ComTech said Thursday.

Retailers climbed 0.3 percent, the second-biggest gain among 24 groups in the S&P 500. Best Buy rose 2.4 percent to $40.55 and Coach jumped 1.4 percent to $57.90. Gap and Tiffany & Co. advanced, while Macy's and Kohl's fell after erasing earlier gains.

Millions of Americans were expected to hit the malls for Black Friday. The cost of hedging against losses in U.S. retailers has slipped to the lowest level in more than three years as investors speculate that an improving labor market and falling gas prices will stimulate holiday sales.

U.S. retail sales climbed at a faster-than-expected pace in October, a measure of consumer sentiment beat estimates this month and jobless claims fell to their lowest since September last week, signaling a strengthening U.S. economy. Gasoline prices are near their lowest since February 2011, while house prices are climbing at the fastest rate since 2006.

Sales are projected to advance 2.4 percent this holiday, the smallest increase since 2009, the year the recession ended, according to researcher ShopperTrak. Faced with six fewer days between Thanksgiving and Christmas than last year, retailers are pouring on the discounts to lure customers. Many chains opened earlier than ever this year to win market share.

"The general mood is that we're going to have growth this year in terms of holiday season shopping, though probably less than before the crisis," Aaron Izenstark, co-founder and chief investment officer of Iron Financial's Iron Strategic Income Fund in Northbrook, Ill., said by phone. "There is an expectation in the market that it has started out on a positive note, so I do think that is definitely driving thoughts today in the marketplace."

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With assistance from Bloomberg reporters Cotten Timberlake in Washington, Lindsey Rupp in New York and Namitha Jagadeesh and Alexis Xydias in London.