SYDNEY--BHP Billiton Ltd. (BHP.AU) swung to its worst-ever loss and cut its final dividend by 77% on-year as the world's No. 1 miner by market value recorded large write downs and grappled with a slump in commodity prices.

The Melbourne, Australia-based miner on Tuesday reported a net loss of US$6.39 billion for the year through June, compared to a net profit of US$1.91 billion the 12 months prior. A loss of US$5.8 billion was the median of eight analyst forecasts compiled by The Wall Street Journal.