Building Apple products has become a side hustle for China's biggest EV maker

Apple products say on the box "assembled in China," leaving the mystery of who did the assembling. Owners of a new iPad might be surprised to learn one of the answers: China's biggest electric-vehicle maker.

- Yang Jie

BYD, known globally as Tesla's most formidable EV competitor, has a second business manufacturing electronics, and it has grown to assemble more than 30% of Apple's tablets, according to industry executives and analysts.

The Chinese company said it had more than 10,000 engineers and around 100,000 employees dedicated to the "fruit chain," the local term for Apple's supply chain.

The combination of brand-name carmaker and contract electronics manufacturer makes sense to BYD executives, who say both businesses draw on the company's core competence of making precision devices at low cost.

Apple's rising dependence on two China-based contractors—BYD and iPhone assembler Luxshare—points to the difficulty of shedding Chinese manufacturing. The U.S. push to limit imports from the country is likely to expand in the second Trump administration.

Apple has been diversifying its supply chain to countries such as India and Vietnam and often turns to Chinese partners for expertise.

"We could not do what we do without them," Apple Chief Executive Tim Cook told Chinese state media on a visit to Beijing in late November, his third to China this year. In the first Trump administration, Cook successfully lobbied the president to exempt electronics including the iPhone from a tariff on Chinese-made goods.

An EV resembles a smartphone on wheels because both rely on batteries, chips and software. The blending of cars and phones is increasingly part of everyday business in China. BYD, which stands for "build your dreams," supplies parts and contract manufacturing for both.