The companies include HNA Group, Dalian Wanda Group Co., Anbang Insurance Group [ANBANG.UL], Fosun International Ltd (>> Fosun International Limited) and Zhejiang Luosen, the firm behind the purchase of A.C. Milan football club earlier this year, one of the sources said.

Chinese financial journal Caixin reported on the investigation earlier on Thursday.

The China Banking Regulatory Commission (CBRC) made the request as it moves to better control potential systemic risk as domestic companies move to acquire more assets in global markets.

Liu Zhiqing, deputy director general of the prudential regulation bureau of the CBRC, declined to comment on the reported communication to banks.

Shares in several of the companies whose loans the banks were asked to assess fell sharply on Thursday.

Shares in Fosun International fell as much as 9.6 percent in Hong Kong trading on Thursday, while shares of HNA Holding Group Co Ltd (>> HNA Holding Group Co Ltd) fell more than 6 percent.

Earlier on Thursday, Dalian Wanda Group denied as "malicious speculation" that some Chinese banks had ordered the sale of its bonds. Shares in Wanda Film Holding Co. (>> Wanda Film Holding Co Ltd) fell 10 percent, before they were suspended from trading in Shenzhen.

(This version of the story corrects to show loans being assessed, paragraph six)

(Reporting By Shu Zhang, Matthew Miller and Kevin Yao in Beijing and Yan Jiang in Hong Kong; Editing by Robert Birsel)