ASX-listed global insurer QBE has announced yet another profit downgrade, preparing the market for a $US1.2 billion ($1.5 billion) after tax loss ahead of its full-year to December results.

In an announcement to the ASX on Tuesday, the insurer further downgraded its combined operating ratio guidance to 104 per cent, above its target range of 100 to 102 per cent as was outlined in October.