Rio Tinto has been trying to reduce its debt
There has been strong take-up from existing share holders for Rio Tinto's cash-raising exercise.
The mining giant was trying to raise $15.2bn (£9.3bn) from shareholders in its UK and Australian listings.
It has announced that 96.97% of the £7.1bn of shares available in London were taken up. It has not yet released details of the Australian issue.
It has also confirmed that its biggest shareholder, China's Chinalco, took up its full entitlement.
Chinalco owns about 9% of the combined listing, having initially bought into the group in February 2008 at £60 a share, near the peak of its share price.
Rio Tinto's shares closed on Wednesday at £21.58 a share in London. The results of the Australian share offering are due to be announced on Friday.
In February, Rio Tinto announced that it would be receiving a $19.5bn investment from Chinalco, which would have increased the Chinese company's stake in Rio Tinto to 18% from 9%.
However, in June, Rio Tinto announced it was scrapping the deal with China's Chinalco in favour of a tie-up with rival giant BHP Billiton, and also announced plans for its huge $15.2bn rights issue to raise funds.
Rio Tinto is seeking to reduce the $38bn of debt it took on to buy the Canadian aluminium group Alcan in 2007.