Australian shares have lost ground after insurer QBE flagged that it would post a $250 million loss for calendar 2013, prompting shocked investors to wipe more than $4 billion from the value of one of the ASX's 20 biggest companies.

Australian shares have lost ground after insurer QBE flagged that it would post a $250 million loss for calendar 2013, prompting shocked investors to wipe more than $4 billion from the value of one of the ASX's 20 biggest companies.