Toshiba said earlier this year it would consider offers as long as it retained majority control over Westinghouse.
Toshiba paid $4.16 billion in 2006 for a 77% stake in Westinghouse. In 2007, Toshiba sold a 10% stake in Westinghouse to Kazatomprom of Kazakhstan, leaving the company with 67% of Westinghouse.
But Toshiba's stake will jump to 87% in January when a sale from The Shaw Group Inc. (NYSE: SHAW) becomes final. Shaw in September 2011 exercised an option to sell its stock after it agreed to be taken over by rival Chicago Bridge & Iron.
An 87% stake would give Toshiba too much exposure to a nuclear industry rattled by the March 2011 accident at Japan's Fukushima nuclear power plant.