Apparently there is a big shortage for ABF (Ajinomoto build-up film) substrate, which is big part of PCB manufacturing (see for example https://www.hardwaretimes.com/ps5-supply-to-be-affected-by-a..., https://www.digitimes.com/news/a20201214PD202.html).

Big suppliers of ABF substrate includes multiple companies from Taiwan Unimicron, Kinsus Interconnect, and Nan Ya PCB, which all trade in the Taiwan stock market.

I considered investing in those companies...but seems like only Nan Ya has been showing an upward trend. Perhaps we are still early?