Shares in Saudi Arabia, OPEC's biggest oil producer, slumped the most in 10 months Saturday after crude fell to the lowest since October as employment reports in the US and Europe signaled fuel demand may tumble. Saudi stock benchmark Tadawul All Share tumbled 4.22 percent, the biggest drop since Aug. 6, to 6,681.18 points at the close. The measure lost 7.7 percent in May, the biggest monthly decline in two years. Oil plunged nearly 4 percent Friday as a bleak report on US job growth heightened worries about a slowing global economy and waning oil demand. Sobering economic news from China and Europe also contributed to the drop. West Texas Intermediate, the benchmark for oil in the US, fell $3.30, or 3.7 percent, to $83.23 per barrel, the lowest price since early October. The drop adds to a 17 percent decline in May. Brent crude, which is used to price international oil, lost $3.44, or 3.4 percent, to $98.43 per barrel, its lowest price since January 2011. Al Rajhi Bank, the Kingdom's largest bank by market value, retreated to the lowest since January and Saudi Basic Industries Corp. (Sabic), the world's biggest petrochemical maker, slid 3.7 percent. Al Rajhi declined 3.1 percent to SR70.50, the lowest level since Jan. 4. Sabic fell to SR90, the lowest close since Nov. 27. "Oil prices are down to low levels and this is one of the reasons why the market is down," said Riyadh-based Turki Fadaak, head of research at Albilad Investment Co. "The global economic reports and Europe's debt problems are also pressuring the market, but this is more of a psychological pressure than anything else, because the link between the Saudi economy and Europe are weak." US stocks dropped more than two percent Friday, with the Dow turning negative for the year for the first time, after poor labor market figures showing a meager 69,000 jobs were added in May. That combined with dismal data on industry from the US, Europe, China and elsewhere to produce a picture of a sharply slowing global economy, sending bulls for the doors on Wall Street. The Dow Jones Industrial Average closed down 274.88 points (2.22 percent) at 12,118.57. That left the Dow down 0.81 percent for the year, the first time the blue-chip index has gone into the red in 2012. The broad-based S&P 500 fell 32.29 points (2.46 percent) to 1,278.04, while the Nasdaq Composite sank 79.86 (2.82 percent) to 2,747.48. European stocks declined for the fourth week in five.