Oil sinks as OPEC deal seen unlikely; stocks dip

NEW YORK (Reuters) - Oil prices tumbled on Friday on signs that Saudi Arabia and Iran continue to disagree over output limits ahead of a meeting next week aimed at freezing production, while global stock indexes dipped.

Energy shares led declines in U.S. stocks, with the S&P energy index .SPNY ending down 1.3 percent, But the S&P 500 and a world stock index registered their best weekly gains in about two months.

Sources said Saudi Arabia did not expect a decision in Algeria, where the Organization of the Petroleum Exporting Countries and other big oil producers are set to convene for the Sept. 26-28 talks.

Brent crude oil LCOc1 shed 3.7 percent to settle at $45.89 a barrel, while U.S. crude CLc1 slumped 4 percent to $44.48, both paring strong weekly gains.

Concern about global oversupply has depressed oil prices since mid-2014.

The day’s decline in world stock indexes also came as investors locked in gains from earlier this week fueled by optimism that the U.S. Federal Reserve will hold off raising interest rates in the near term.

“I just think after a few strong days and a little weakness in energy that folks are taking some profit before the weekend,” said Gary Bradshaw, portfolio manager with Hodges Capital Management in Dallas.

The Dow Jones industrial average .DJI ended down 131.01 points, or 0.71 percent, at 18,261.45, the S&P 500 .SPX lost 12.49 points, or 0.57 percent, to 2,164.69 and the Nasdaq Composite .IXIC dropped 33.78 points, or 0.63 percent, to 5,305.75.

Facebook FB.O shares fell 1.6 percent and were one of the biggest drags on the S&P. The Wall Street Journal reported that the social media company overestimated viewing time for video ads.

MSCI's all-country world stock index .MIWD00000PUS shed 0.6 percent but rose 2.2 percent for the week, its biggest weekly gain since mid-July. Europe's STOXX 600 .STOXX closed down 0.7 percent.

U.S. Treasury prices rose, with benchmark yields hitting two-week lows as a result of safe-haven demand for bonds due to losses in Wall Street stocks.

Treasury prices have risen following the Fed’s decision to leave interest rates unchanged and the Bank of Japan’s policy change on Wednesday.

U.S. benchmark 10-year Treasury notes US10YT=RR were up 4/32 in price for a yield of 1.618 percent, down more than 1 basis point from Thursday. Earlier on Friday, it touched 1.606 percent, its lowest since Sept. 9, Reuters data showed.

In the foreign exchange market, the dollar index was nearly flat as investors kept positions tight ahead of Monday’s U.S. presidential debate.

The dollar index .DXY, which measures the dollar against six major world currencies, was flat on the day at 95.472. It fell 0.7 percent for the week, its worst weekly performance since the week of Aug. 18.

Gold steadied in a lackluster session as the U.S. dollar flattened. Spot gold XAU= was up 0.03 percent at $1,337.01 an ounce.

Additional reporting by Barani Krishnan and Lewis Krauskopf in New York and Rania El Gamal and Dmitry Zhdannikov in London; Editing by Bernadette Baum and Dan Grebler