Small factories with tiny profit margins have played a central role in China’s international competitiveness. Many could now face disaster.

But shares in TSMC, the world's largest contract chipmaker have slipped, after US President Donald Trump said he would announce a tariff rate on imported semiconductors over the next week. He did add however, that there would be flexibility on some companies in the sector.

Imposition of new tariffs on nearly every country adds to concerns in Europe and Asia about relying on America.