Nov. 9 (Bloomberg) -- The following companies may have unusual price changes today in Latin American trading. Stock symbols are in parentheses and share prices reflect the previous close.

The MSCI Latin America Index fell 0.4 percent to 3,942.24. In Brazil, preferred shares usually are the most-traded class of stock.

Argentina

Tenaris SA (TS AF): The world’s biggest maker of seamless pipes used to extract oil and gas said operating costs will decrease in the “coming quarters.” It also said Petroleos Mexicanos may drill about 600 wells at Chicontepec next year, about a third of the wells that the state-owned company planned. Tenaris fell 1.9 percent to 74.10 pesos when it last traded in Buenos Aires on Nov. 5.

Brazil

GVT (Holding) SA (GVTT3 BZ): The Brazilian telephone company said funds managed by Nomura International Plc holds 6.3 percent of the company’s total shares, including 5 percent of its voting shares. The stock rose 1.4 percent to 53.35 reais.

Light SA (LIGT3 BZ): Brazil’s second-largest electricity distributor said profit declined to 67.4 million reais ($39.2 million) in the third quarter, compared with 204 million reais a year earlier. It said separately it plans to buy back as many as 6.6 million voting shares over a year starting on Nov. 10. Light rose 0.1 percent to 24.63 reais.

Chile

Empresa Nacional de Electricidad SA (ENDESA CI): Chile’s biggest power generator said Chief Executive Officer Rafael Mateo has offered his resignation. Endesa Chile rose 0.1 percent to 819.52 pesos.

Mexico

Wal-Mart de Mexico SAB (WALMEXV MM): Latin America’s largest retailer said October same-store sales rose 5.1 percent from a year ago to 21.7 billion pesos ($1.6 billion). Walmex rose 0.3 percent to 48.41 pesos.

To contact the reporter on this story: Emily Schmall in Mexico City at Eschmall@bloomberg.net

Last Updated: November 8, 2009 21:00 EST