By Nathan Gill

     Aug. 11, 2008 (Bloomberg) — Tenaris SA fell the most since April 2003 in Buenos Aires on speculation a stronger U.S. dollar will hurt commodity prices and curb demand for its products.

     The world’s biggest supplier of seamless pipes used by oil and gas producers retreated 8.2 percent to 78 pesos. Luxembourg-based Tenaris dropped to the lowest level since March 25.

     Commodities slumped as signs of slowing global growth sent crude oil, gold and silver tumbling and an index of 24 raw materials into a bear market, or a decline of 20 percent from its recent high. The decline was fueled by the dollar’s sixth consecutive advance. The U.S. Dollar Index added 0.4 percent to the highest since February.

     “Tenaris is falling because of the gain in the U.S. dollar,” Cristian Reos, head of research at Allaria Ledesma y Cia., said in a telephone interview from Buenos Aires. “All commodities are experiencing strong falls.”

     Socotherm Americas SA, a producer of steel pipe coatings, fell 9.6 percent to 12.20 pesos, the steepest decline since the shares began trading in November 2006. Socotherm had a net loss of 29.8 million pesos ($9.81 million) for the first half, the Buenos Aires-based company said in statement posted on the stock exchange today. It didn’t give the year-ago result.