Any veteran investor will tell you that financial markets overshoot when trouble hits, but what if that market is the world's second-largest economy and the government has decided the rules of the game have changed?

China's monthslong regulatory crackdown has included big names in e-commerce, the gig economy, exam cramming and most recently online insurance. Close to $1 trillion (about ¥109 trillion) in market value has been wiped off China Inc. since February.

For big firms that also list on markets like Wall Street because it brings in international investment, 2021 is already the worst year since the global financial crisis.