Jack Ma, CEO of Alibaba Group.

Shares of Yahoo Inc. plummeted Wednesday over concerns that its stake in Chinese e-commerce giant Alibaba Group may lose value after Alibaba sold its online payment business.

According to Yahoo's filing with the Securities Exchange Committee, Alibaba has spun off its successful online payment business Alipay to a separate company owned by Alibaba CEO Jack Ma. Yahoo owns 43 percent of Alibaba.

Yahoo and Softbank Corp., another Alibaba Group shareholder, are in talks with Alibaba Group's management about the terms of the shift and related issues.

Analysts say Alibaba's move will make it easier for Alipay to obtain an operating license from the People's Bank of China because a domestic company can more readily acquire such a license.

"If Alipay is restructured as a Chinese company, it will help the company to obtain a license from China's central bank more quickly," Jordan Rohan, an analyst at an American investment firm Stifel Nicolaus, wrote in a research note. "There are concerns that the People's Bank of China may prevent a foreign-owned company from entering the country's online payment business."

Rohan also thought the shift in Alipay's ownership may have a negative effect on Yahoo, because investors will think the change diminishes the value of Yahoo. In a worst-case scenario, profit from Alipay could be diverted to the new property, away from Alibaba Group and Yahoo, he wrote.

Alipay is the world's largest online payment platform by number of users and transaction volumes. It had 550 million users compared with Paypal's 94.4 million by the end of last year.