Zhou Nushi, a retired factory worker in Shanghai, would like to buy shares of Alibaba Group Holding Inc as the Chinese e-commerce company goes public in what may be the biggest initial share sale ever.

The trouble is she can't. Like most Chinese, she doesn't have the financial resources and extensive qualifications necessary to invest in securities listed outside the mainland. Alibaba, based in Hangzhou, is listing its stock in the United States.

"I'm a little confused about why you can't invest in a Chinese company if you're Chinese," says Zhou, clad in gray shorts as she passes time in front of the digital stock ticker at a local branch of Guotai Junan Securities Co in Shanghai.