Rio Tinto offers big reward to investors

Rio Tinto Group will pay a much higher dividend than expected and buy back $500 million of shares after the world's second-biggest mining company reported its first gain in annual profit since 2013.

Higher iron ore prices boosted underlying profit by 12 percent to $5.1 billion in 2016, London-based Rio said on Wednesday.

The dividend fell 21 percent to 170 cents a share, reflecting a new policy aligning the payout to earnings.