For two decades, Chinese tech firms have flocked to the U.S. stock market, drawn by a friendly regulatory environment and a vast pool of capital eager to invest in one of the world's fastest-growing economies. Now, the juggernaut behind hundreds of companies worth $2 trillion appears stopped in its tracks.

On July 10, Beijing announced that almost all businesses trying to go public in another country will require approval from a newly empowered cybersecurity regulator. This decision amounts to a death knell for Chinese initial public offerings (IPOs) in the United States, according to long-time industry watchers.

"It's unlikely there will be any U.S.-listed Chinese companies in 5 to 10 years, other than perhaps a few big ones with secondary listings," said Paul Gillis, a professor at Peking University's Guanghua School of Management in Beijing.