NEW YORK (AP) — US stocks opened lower on Monday amid concerns over China's economy. Silver fell again, dropping to its lowest level in over four years.

KEEPING SCORE: The Standard & Poor's 500 index dropped seven points, or 0.4 percent, to 2,003 as of 9:52 a.m. Eastern. The Dow Jones industrial average slipped 27 points, or 0.2 percent, to 17,251. The Nasdaq composite dropped 25 points, or 0.5 percent, to 4,555.

CHINA WORRIES: Investors are nervous about China following a run of soft economic data that suggests growth in the world's second-largest economy is slowing. On Tuesday, HSBC publishes its closely watched gauge of Chinese manufacturing activity.

THE QUOTE: "There's growing concern over the state of the Chinese economy," said Joao Monteiro, analyst at Valutrades.

EUROPEAN MARKETS: Germany's DAX was flat around 9,800 and France's CAC-40 fell 0.1 percent to 4,457. Britain's FTSE 100 lost 0.8 percent to 6,791.

M&A CHEMISTRY: St. Louis-based chemical firm Sigma-Aldrich surged $35.33, or 34 percent, to $137.60 after agreeing to be acquired by Merck, a German drug company. Merck is paying $140 a share from Sigma-Aldrich, a premium of 37 percent over Friday's closing price.

ASIA'S DAY: The concerns over China's economy sent the Shanghai index down 1.2 percent to 1,332.22. Hong Kong's Hang Seng lost 1.4 percent to 23,955.67. Elsewhere, Tokyo's Nikkei 225 fell 0.7 percent to 16,205 while South Korea's Kospi declined 0.7 percent to 2,039.27.

CURRENCIES: The Japanese yen has been trading at six-year lows against the dollar in anticipation that the U.S. Federal Reserve will raise interest rates next year while the Bank of Japan will maintain an easy monetary policy. On Monday the dollar edged up to 109.12 yen. The euro slipped to $1.2840.

BONDS: U.S. government bond prices rose. The yield on the 10-year government bond fell to 2.57 percent from 2.58 percent.

SILVER'S FALL FROM GRACE: Silver continued its recent descent, falling to its lowest level since the summer of 2010. The price of an ounce of silver fell 1.4 percent to $17.59. Precious metals, including gold, have been pressured by the recent strength of the dollar, low global inflation and rising stock markets. Gold is trading at its lowest price since the start of the year, $1,214 an ounce.

ENERGY: Benchmark crude oil fell 20 cents to $91.45 a barrel on the New York Mercantile Exchange.

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