Over $28 billion was wiped from the value of Australian shares, which slumped to a nine-month low, as fresh pessimism swept world markets on renewed concerns about the Greek debt crisis and health of the United States' economy.

Over $28 billion was wiped from the value of Australian shares, which slumped to a nine-month low, as fresh pessimism swept world markets on renewed concerns about the Greek debt crisis and health of the United States' economy.