China's National Council for Social Security Fund is an unlikely candidate to buy into US private equity groups, but the disclosure in yesterday's Financial Times that it has held preliminary talks about buying stakes in companies such as Carlyle and Kohlberg Kravis Roberts underlines how dramatically China's global ambitions have grown.

The fund joins a number of large state institutions investing overseas, such as China Investment Corp, the newly-established sovereign fund, and China Development Bank, a specialist lender for infrastructure projects.