 As the reserves continue to grow, the central bank is aiming to boost investment returns on its foreign-exchange holdings by making somewhat riskier but higher-yielding investments.Pronouncements of Chinese officials are consequently closely scrutinised; each trade is reportedly up to US$1 billion.As part of diversification in 2008, SAFE acquired small stakes in dozens of companies including British companies Rio Tinto, Royal Dutch Shell, BP, Barclays, Tesco and RBS.