CIC was created in 2007 with USD 200 billion to make better use of China's colossal foreign exchange reserves, which amounted to USD 3.73 trillion this March.
Its total assets expanded to USD 746.73 billion by the end of 2014, an increase of USD 93.5 billion, CIC said in its annual report.
But returns on the overseas portfolio dropped to 5.47 per cent, down from 9.33 per cent in 2013 and the weakest since 2011, according to the document.
"CIC... Remained focused on identifying the investment opportunities that China's economic success, economic structural upgrading, and global outreach present," he added.
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The document did not specify the size of CIC's foreign investment portfolio, but said 44 per cent of it was in publicly-quoted shares, with almost half of that - 45.6 per cent - in US equities.
Fixed income products accounted for 14.6 per cent of the portfolio, with advanced economies' sovereign bonds accounting for 57.4 per cent of that, it added.
It owns 65.5 per cent of Bank of China, the document showed, 57.3 per cent of China Construction Bank, 40.3 per cent of Agricultural Bank of China, and 35.1 per cent of Industrial and Commercial Bank of China, the world's biggest lender.
In 2012, CIC acquired 8.68 per cent of British utility company Thames Water - the largest water and sewage service provider in Britain - for an unspecified price.
Later in the year, it bought a 10 per cent stake in London's Heathrow Airport for 450 million pounds (now USD 703 million).