China's National Social Security Fund (NSSF) has asked its fund managers to cut their holdings in mainland-listed companies from 90% to 70% within one month, the South China Morning Post reported, citing state media. The move, which will see as much as US$8 billion in shares sold, comes amid growing concerns about a potential stock market correction. The Shanghai Composite Index has risen more than 120% so far this year. According to one source close to the financial authorities, recent warnings by the likes of Warren Buffett and Alan Greenspan have "definitely affected the top pension fund managers." About 20 fund management companies are designated to invest NSSF assets and analysts warned that the selloff could lead to stock market volatility. According to Wind Information, a Shanghai financial data provider, the NSSF held shares in 137 firms on September 30, compared with 172 on June 30.