Taiwanese prosecutors raided IC substrate leader Unimicron, a bad turn for a stock that hit a record high the very same morning.

• Investigators searched the company's Hejiang plant in Zhongli and took away two vice presidents, an accountant, and more than ten staff for questioning, along with four laptops and a pile of documents.
• The suspicion is that Chinese-made substrates were shipped through Taiwan and stamped "Made in Taiwan" to dodge high US tariffs.
• Prosecutors are also looking at cooked books used to dress up results, plus insider trading on that non-public information.
• The tip reportedly came from someone inside the company who had been quietly gathering evidence for a long time.
• Unimicron shares touched an all-time high early in the day, then closed lower before news of the raid broke.

Outlook: Prosecutors say they will explain only once the case is clearer, and the stock is likely in for a rough stretch while that hangs over it.