But the U.S. is the largest country in the fund, at 49%, followed by Chile, at 20%, and Japan, at 10%, before the allocations get much smaller. In addition to mining companies, the ETF owns companies that make the batteries. Nissan Motor Co., seeking to be the world's biggest producer of electric vehicles, said lithium-ion battery packs on its rechargeable Leaf hatchback will have an eight-year warranty.

Customer concerns that electric cars may not be as reliable as gasoline-engine autos led the Yokohama, Japan-based Company to set the warranty at eight years or 100,000 miles on the first-generation Leaf powertrain, Carlos Tavares, Nissan's executive vice president and head of operations in the Americas, said today at a conference in San Jose, California.

"We have a warranty that is matching market standards," Tavares said in an interview. "We checked that those were matching the customers' expectations through market research."

Nissan, Japan's third-largest automaker plans to sell as many as 25,000 units of the $32,780 Leaf in the U.S. during the model's first year, following its introduction late this year. Chief Executive Officer Carlos Ghosn has set a goal of expanding battery and electric vehicle production to as many as 500,000 vehicles by the end of 2012.

The durability of lithium-ion batteries hasn't been proven yet as vehicles that use them are just beginning to come to market this year.

Profitability

About 17,000 U.S. consumers have paid $99 to reserve one of the initial models, Nissan said today.

The price for the car, which the company says will go 100 miles (160 kilometers) per charge, will eventually allow the Leaf to be profitable even with its new battery technology and electronics, Tavares said.

"We're not going in this strategic direction because we just want to test the water," Tavares said. Nissan's plan is for the Leaf to be "as profitable as a conventional vehicle," he said.

Tavares also said today that initial deliveries of the Leaf will begin in December for customers in California, Oregon, Washington, Arizona and Tennessee. The model is to be sold next in Hawaii and Texas, with availability across the U.S. expected by the end of 2011, he said.

Nissan's North American operations are based in Franklin, Tennessee.