China's insurance regulator has given go-ahead to another seven small and medium-sized insurance companies to invest through trust services in the country's bullish stock markets.

The insurance companies are Sunshine Insurance, Jiahe Life, Dragon Life, Dazhong Insurance, AVIVA-COFCO Life, Yingda Taihe Life, and Changjiang Pension Insurance, according to China Insurance Regulatory Commission (CIRC).

Their investment ceiling is ten percent of their assets at the end of last year and for some insurers the ceiling is five percent, the CIRC said.

The approval raised the number of insurers that can do trustee investment to more than 20, Tuesday's Shanghai Securities News cited an unnamed source as saying.

Only nine local insurers that have asset management businesses and the U.S.-funded AIA China have been given approval for direct investment in the Chinese mainland stock markets.

In July, the CIRC doubled the equities investment cap for insurance capital from five to ten percent to allow more opportunities for higher earnings on the heated stock markets.

China's benchmark Shanghai Composite Index rose 0.41 percent to 5,715.89 points on Tuesday. It has jumped 113.6 percent since the beginning of the year.

The seven insurance firms, most established less than five years ago, would have little impact on the stock markets as their assets were usually small in scale, analysts said.