Beijing, Sep. 23 - The value of China's social security fund had reached 400 billion yuan (53.3 billion U.S. dollars) by the end of June this year, said Wang Zhongmin, deputy director of China's National Council for Social Security Fund (NSSF).The security fund reported a profit rate of 15.2 percent in the first half of 2007, making an operating profit totaling 147.9 billion yuan (19.7 billion U.S. dollars), Wang told a social security forum.The NSSF has kept to the principle of safety-oriented investment and long-term investment, which guaranteed a stable return and an increasing profit rate for the fund, said Wang."The fund is still insufficient to the country's huge population of 1.3 billion," said Wang, saying the ideal amount of social security fund should be two trillion yuan (266 billion U.S. dollars).In case of an annual profit rate of no less than 5 percent, a two-trillion-yuan fund could generate 100 billion yuan (13.3 U.S. dollars) in profit each year, said Wang, adding that will allow the fund to satisfy the needs of social security while keeping its principal intact.China's social security fund was established in August 2000 to prepare for the country's coming peak of aging population.