When China’s BYD recently overtook Elon Musk’s Tesla as the global leader in sales of electric vehicles, casual observers of the auto industry might have been surprised.

But what’s caught other carmakers around the world off-guard is something else about BYD, which is backed by Warren Buffett’s Berkshire Hathaway: its low prices.

“No one can match BYD on price. Period,” Michael Dunne, CEO of Asia-focused car consultancy Dunne Insights, told the Financial Times. “Boardrooms in America, Europe, Korea and Japan are in a state of shock.”

BYD can keeps its costs low in part because it owns the entire supply chain of its EV batteries, from the raw materials to the finished battery packs. That matters because a battery accounts for about 40% of a new electric vehicle’s price.