Firms Hit by Chinese Hackers Didn't Tell Investors

Three U.S. public companies identified as Chinese hacking victims didn’t report the theft of trade secrets and other data to investors, despite rules designed to disclose significant events. Two of the companies -- aluminum maker Alcoa Inc. and metals supplier Allegheny Technologies Inc. -- said the thefts weren’t “material” to their businesses and therefore don’t have to be disclosed under Securities and Exchange Commission rules designed to give investors information that may affect share prices.