Net profit in the first six months of the year at BYD, China’s biggest maker of electric vehicles, fell by 29% to 1.17 billion yuan, or $180 million, amid rising material costs, the company reported in a filing Friday evening. Revenue at the Warren Buffet-backed business increased by 53.6% to 89.1 billion yuan. (Click [here](//www1.hkexnews.hk/listedco/listconews/sehk/2021/0827/2021082701942.pdf) for announcement.) China electric vehicle makers have won the attention of global stock investors in the past three years in part through hugely successful U.S. IPOs by upstarts Nio, XPeng and Li Auto. They’ve all as much as doubled since listing owing to growth in...