China is cracking down on stocks that trade on U.S. exchanges. Here’s what it means if you hold them

China’s most powerful companies — including Didi, Alibaba and Tencent — are suddenly under immense scrutiny as country vows to crack down on domestic companies that list on U.S. exchanges. That move could upend a $2 trillion market loved by some of the biggest American investors.

Beijing is stepping up its oversight on the flood of Chinese listings in the U.S., which are overwhelmingly tech companies. The State Council said in a statement Tuesday that the rules of “the overseas listing system for domestic enterprises” will be updated, while it will also tighten restrictions on...