Chinese battery and electric vehicle maker BYD reveals off a design of its Han EV series at the 2020 Beijing vehicle show.Evelyn Cheng|CNBCBEIJING– Warren Buffetts Berkshire Hathaway conglomerate has a bigger stake in Chinese electric car manufacturer BYD than it does of General Motors, according to a letter to shareholders.Berkshire Hathaway holds an 8.2% stake in Hong-Kong noted BYD and is the companys eighth-largest holding by market worth as of Dec. 31, according to the letter which was launched on Saturday.In contrast, the firm held 3.7% of General Motors, the 15th-largest holding.Shares of BYD are up more than 300% over the last 12 months. Those of GM have climbed 65% during the very same time period.