BHP Billiton posts another monster profit of US$9.9 billion - the first profit fall in three years.

BHP Billiton has posted a drop in net profit for the first half of the financial year, the first time profits have fallen in three years.

Here's my analysis broadcast on the Perth Edition of AM.

The world's largest miner says profit for the six months to December totalled $9.94 billion, a 5.5 per cent fall compared with the same time a year earlier.

The company's short-term outlook was mixed, but chief executive Marius Kloppers said Australia's economic stability should offer protection in the long term.

BHP has also warned that markets are set to remain volatile because of the woes in Europe and sluggish global growth.