China's central bank has granted its approval to eight more foreign banks, including the Hong Kong units of Citigroup Inc. (C) and Bank of Tokyo-Mitsubishi UFJ Ltd., to trade in the domestic interbank bond market as part of a trial program under which offshore yuan can be invested in onshore yuan bonds.

The six other banks are the Hong Kong units of Agricultural Bank of China Ltd. (1288.HK) and China Construction Bank Corp. (0939.HK), as well as Nanyang Commercial Bank Ltd., Wing Lung Bank Ltd., Wing Hang Bank Ltd. (0302.HK), and Chiyu Banking Corp.

The People's Bank of China previously approved 11 foreign banks, including Standard Chartered PLC (STAN.LN) and HSBC Holdings PLC (HBC), to trade in the interbank bond market after it allowed foreign financial institutions participating in the cross-border yuan-settlement program to reinvest their yuan proceeds in the mainland China bond market in August.

The trial program includes Hong Kong, Macau and foreign banks that participate in the yuan-settlement program, as well as overseas central banks. China's interbank bond market includes over 10 types of bonds, such as government bonds and policy-bank bonds.

-Wynne Wang contributed to this article, Dow Jones Newswires; (86-21) 6120-1200; wynne.wang@dowjones.com