While that represented close to 10% of the 4,399 financial institutions, including banks and financial companies, that were covered in a central bank's report, the PBOC said in a statement that the high-risk institutions accounted for just 2% of country's banking assets.

Although the overall number of high risk institutions declined significantly, rural banks and rural cooperatives remained at higher risks than others, PBOC said.

Geographically, the northern Liaoning, Gansu and Inner Mongolia regions contain more high-risk institutions than other provinces.

One unnamed financial company was given the lowest "D" rating, meaning it has been made bankrupt or been taken over by the regulators.

(Reporting by Cheng Leng, Zhang Yan and Ryan Woo; Editing by Andrew Cawthorne & Simon Cameron-Moore)