HONG KONG, Oct 28 (Reuters) - China Life Insurance Co Ltd , the country’s biggest insurer by market value, said on Wednesday third-quarter net profit fell by 74 percent on plunging investment income and rising claims.

Net profit in the quarter ended September fell to 2.35 billion yuan ($369.57 million) from 9.15 billion yuan a year earlier, the company said in a stock exchange filing in Hong Kong.

China’s life insurance industry as a whole has reported declining earnings growth this year, as the country’s June-August stock market turmoil hammered their investment portfolios.

The big swings in Chinese insurers’ financial results are partly due to local accounting rules that require them to include changes in the value of their investment portfolios in their profit figures.

China Life’s shares closed down 2.7 percent in Shanghai ahead of the results announcement, underperforming the benchmark Shanghai Shenzhen CSI 300 index which fell 1.9 percent.

China Life rival Ping An Insurance Group on Tuesday reported a 32 percent rise in profit for the quarter. ($1 = 6.3588 Chinese yuan renminbi) (Reporting By Lawrence White; Editing by Miral Fahmy and Muralikumar Anantharaman)