Activist fund Elliott has built up a $1-billion stake in Anglo American, a filing showed on Friday, after the London-listed miner became a takeover target by bigger rival BHP Group.
Elliott disclosed total interests of about 2.5% in Anglo American, according to a filing with the UK's Takeover Panel. That makes it one of the miner's top 10 shareholders, as per LSEG data.
The disclosure confirms media reports from earlier in the day, which pushed up shares in Anglo.
Shares were up about 3.5% to 26.50 pounds by 14:42 GMT in London, hitting their highest level in a year.
Anglo rejected rival miner BHP Group's BHP.AX 31.1 billion pound ($39 billion) takeover proposal earlier on Friday, saying the bid significantly undervalued the London-listed miner and its future prospects.
Investors and analysts have also dismissed BHP's offer as opportunistic.
Elliott also holds a small interest in BHP, according to another filing, alongside total short positions of about 0.1% in the Australian miner.
New York-based Elliott in 2017 built a roughly 5% stake in BHP, urging it to split off its oil business, scrap its dual listing and return more cash to shareholders. It also agitated against it entering the fertilizer market with its potash project Jansen in Canada.
Shareholders in companies that are party to a potential deal are required by UK takeover rules to disclose their holdings in the target and bidding firms, if they hold over 1%.