MOSCOW (Reuters) – Indebted aluminium giant UC RUSAL has secured a member of the Rothschild family as well as one of southeast Asia's richest men as investors in an IPO that banks say could value the firm at up to $25 billion.

A US hedge fund that made billions of dollars in profit last year is also among the four cornerstone investors for the Hong Kong IPO planned in January by the world's largest aluminium producer, two sources said.

The roughly $2 billion IPO is a major step for the Russian firm, which is trying to raise cash to repay $14.9 billion in debt, and also for Hong Kong, a financial centre trying to attract more publicly traded companies from beyond Asia.