Taiwan's chip-substrate makers are rallying hard on signs that AI chip demand is outrunning supply — good news for Unimicron, Nan Ya PCB, and Kinsus shareholders, less so for chipmakers that need to buy the parts.

• Unimicron and Nan Ya PCB both hit their daily limit-up at the open, and Kinsus and Zhen Ding also jumped, making the group the market's hottest money magnet.
• Goldman Sachs flagged several supply-squeeze signals: key lamination equipment now has delivery waits stretching to 2031, customers are paying premiums to lock in capacity, and makers' order backlogs are growing again.
• The cause is AI: bigger, more complex chips for AI servers, GPUs, and custom ASICs need more high-end ABF substrate, and new factories take years to build and get certified.
• Goldman thinks the shortage is not a short blip and could run through 2028, letting Taiwanese makers with pricing power lift sales and profits first.
• Analysts expect earnings at Unimicron and Nan Ya PCB to multiply this year and grow strongly again next year, though the stocks now trade at rich valuations on those forecasts.

Outlook: As long as AI server orders keep flowing and new capacity stays slow to arrive, substrate makers should keep pricing power, though the stocks have already run far and remain prone to sharp pullbacks when institutional investors take profits.