TSMC is riding high. The Taiwanese chipmaker—sole supplier of artificial-intelligence (AI) chips to Nvidia, the world’s most valuable chip designer—has seen sales more than double since the start of 2020. While other semiconductor firms fret about cooling demand for gadgets and cars, TSMC believes demand for AI is just gearing up. Investors agree, propelling its market capitalisation towards $1trn and into the world’s ten most valuable firms.