China’s central bank and banking and insurance regulator issued draft rules on Friday on the issuance of perpetual bonds by country’s insurance companies.

The new rules aims to improve the capital replenishment and risk resistance of insurance firms, and to protect the interests of investors, the People’s Bank of China and the China Banking and Insurance Regulatory Commission said in a joint statement.

Chinese insurance firms have been allowed to sell bonds in country’s interbank-market since 2015 to strengthen their capital base.

But as regulators strengthen capital requirements including the insolvency ratio on the insurance sector, there is a necessity for regulators to broaden the fundraising channel for insurance firms to boost capital, the joint statement said.

Insurance holding firms are not allowed to issued such perpetual bonds, the draft rules added.

(Reporting by Cheng Leng and Ryan Woo; editing by David Evans)