Updated

China's foreign exchange reserves have fallen to a six-year low following an outflow of capital that prompted Beijing to tighten controls on outbound investment.

Central bank data Tuesday showed reserves declined by about $13 billion in January to $2.99 trillion but still are by far the world's biggest. It was the seventh straight month of decline.

The Chinese central bank has been spending foreign currency to shore up the value of the yuan. Chinese investors also are eroding the reserves by moving money abroad.

That prompted Beijing to tighten controls on the ability of companies and individuals to move money out of the country.