Auto sales in China overtook the United States in 2009 to make it the world's largest car market and it hit a new record last year, rising more than 32 percent to 18.06 million units sold. Last year, BYD's car sales in China hit 519,800 units, up 15.9 percent from 2009 but 13 percent below its target of 600,000.

The Shenzhen-based company, which began as a manufacturer of rechargeable lithium-ion and nickel batteries, fell into the international spotlight when Buffett bought a 9.89-percent stake in it in 2008 for $230 million. At one of the events last year to endorse the company, Buffett described BYD as a "young and energetic" company, and said he believed it would play an important role in the future of new energy technology.