Anglo American told shareholders today that a US$38.91 billion (AUD$59.7 billion) takeover offer from BHP would be “highly unattractive for Anglo American’s shareholders”.

It said there was “uncertainty and complexity inherent in the proposal, and significant execution risks” with BHP’s proposal, that was confirmed this morning by the Australian copper giant.

BHP said today that it made a proposal to Anglo American’s board of directors on April 16 “regarding a potential combination”.

The merger would have created the world’s biggest copper miner with around 10 per cent of global output.

Anglo American’s board unanimously rejected the proposal in a shareholder announcement posted on Friday afternoon Australian time.

Anglo American Chairman Stuart Chambers said the company was “well positioned to create significant value from its portfolio of high quality assets that are well aligned with the energy transition and other major trends”.

“With copper representing 30 per cent of Anglo American’s total production, and with the benefit of well-sequenced and value-accretive growth options in copper and other structurally attractive products, the Board believes that Anglo American’s shareholders stand to benefit from what we expect to be significant value appreciation as the full impact of those trends materialises,” Chambers said.

“The BHP proposal is opportunistic and fails to value Anglo American’s prospects, while significantly diluting the relative value upside participation of Anglo American’s shareholders relative to BHP’s shareholders.

“The proposed structure is also highly unattractive, creating substantial uncertainty and execution risk borne almost entirely by Anglo American, its shareholders and its other stakeholders.”