In the ever-complex US-China economic relationship, the most consequential signals are not always those that command the biggest headlines. Tariffs, summits and disputes over semiconductors and other advanced technology attract understandable attention. However, a quieter change announced in Beijing on June 1 may prove more durable: China’s new State Council regulation on outbound investment, scheduled to take effect on July 1.On its face, the new regulation appears purely administrative. It...