Elliott Investment Management, the activist hedge fund firm led by Paul Singer, holds an approximately $1bn stake in Anglo American, the UK-listed mining company that is the subject of an unsolicited takeover bid from Australia's BHP Group, according to a report by Bloomberg.

The report cites a UK regulatory tiling on Friday in revealing that Elliot holds a 2.5% stake in Anglo American via derivatives exposure to 33.6m of the company's shares.

According to unnamed people familiar with the matter, Elliot built its holding, which makes it one of Anglo American's 10 largest shareholders, over the past few months. The firm also holds a 0.07% short position in BHP, according to another filing.

Shares of Anglo American jumped by as much as 6% in London after news of Elliot's stake broke.

BHP's offer to acquire its smaller rival values the business at £31.1bn ($38.9bn). If a deal is concluded, it would create the world’s top copper producer. However, Anglo American has said that the proposal significantly undervalues the company.

Shares in Anglo American closed 3.2% higher in London on Friday at 2,643.00 pence, giving it a market value of about £32.4bn, having surged by 16% on Thursday on the news of BHP’s approach. The stock is still down more than a third from its peak two years ago.