Chinese Internet companies have been falling in U.S. trading ahead of the impending IPO by by Renren.

Investors are said to be worried that the new listing by China's biggest social-networking website may dillute the market by allowing the company to expand.

Sina dropped 9.5 percent at the close of trading at in New York, its biggest drop since February 2009.

Baidu has slid 5.2 percent.

Sohu.com and NetEase.com also tumbled the most in some 17 months.

Renren is seeking a valuation more than double that of Facebook in its initial public offering, trying to raise as much as 743.4 million US dollars.