BYD Co. shares jumped 7.8% Monday, their biggest gain in 13 months, after reports that the company's Brazil plant received export orders for about 100,000 vehicles to Argentina and Mexico. The rally pushed the Chinese EV leader to the top of the Hang Seng Tech Index, with peers Nio Inc. and Xiaomi Corp. climbing around 5%.

Investor optimism stems from growing evidence that overseas sales will drive BYD's future growth as competition intensifies at home. The company's first two months of 2025 saw sales fall 36% to 400,241 units, though exports are gaining momentum. BYD now targets selling 1.3 million cars abroad in 2026, positioning international markets as a critical profit driver.

The sector-wide rally also reflects expectations of stronger new energy vehicle adoption amid higher oil prices and lower lithium costs. Battery makers joined the advance, with Contemporary Amperex Technology Co. Ltd. shares up 7.9%. Analysts note that European demand could benefit from elevated gas prices, though domestic Chinese EV demand remains less sensitive to fuel costs.