Chris Ratcliffe | Bloomberg | Getty Images
Elliott Management has built a roughly $1 billion stake in miner Anglo American in recent months, a person familiar with the matter told CNBC.
Anglo American shares were up 5%.
News of the activist's position comes as the $43 billion, London-based miner faces takeover interest from BHP, a mining giant with worldwide operations. Anglo rejected BHP's $39 billion takeover offer Friday morning, saying BHP's offer "significantly undervalues Anglo American and its future prospects."
Anglo American declined to comment.
This is a developing story. Please check back for updates.