Globe Specialty Metals Inc.'s deal to sell interests in two silicon metal plants to Dow Corning Corp. could tighten the spot market on both sides of the Atlantic, sources said.

In the $175-million deal, Dow Corning bought a 100-percent interest in Brazilian silicon metal manufacturer Globe Metais Industria e Comercio SA and a 49-percent stake in Globe's silicon manufacturing operation in Alloy, W.Va.

The deal, which will cut the amount of material available to the spot market and boost Beverly, Ohio-based Globe's market share, might also give the sole U.S. silicon metal producer and dominant market player a greater ability to dictate spot prices.

Globe is already a major supplier to Dow Corning and is under contract to supply 30,000 tonnes of silicon metal in 2009 and 20,000 tonnes in 2010, at which point the contract...