Anglo American is about to begin a formal sales process for De Beers, after receiving indications of interest from potential buyers that include two former chief executives of the iconic diamond miner.

An exit from De Beers represents the final step in a sweeping restructuring plan outlined by Anglo CEO Duncan Wanblad last year as the company fended off a takeover approach from BHP Group. Anglo has already agreed to sell its coal and nickel mines and unbundled its platinum business this week.

Former De Beers bosses Gareth Penny and Bruce Cleaver are both leading groups that are potential buyers, as is Australian mining veteran Michael O’Keeffe, according to people familiar with the matter. Anglo is working with advisers who are preparing to start the process, said the people, who asked not to be identified discussing private information.

Anglo American declined to comment, as did Penny and Cleaver. O’Keeffe could not be reached for comment.

Anglo has waited to sell De Beers as the diamond industry grappled with its deepest crisis in decades, after a collapse in Chinese demand and fierce competition from synthetic stones. Anglo wrote down the value of the unit for a second time in February, to about $4.1-billion.

But while prices for rough diamonds have slumped, Anglo’s executives still see De Beers as a trophy asset — the company has said it will be patient in finding a buyer and doesn’t want to destroy value by moving too quickly.

The diamond market is now showing signs of stabilizing, although President Donald Trump’s trade war has created fresh uncertainty and disruption.

Anglo is also examining options for an initial public offering or demerger of De Beers. However, a sale is the preferred and most likely option, the people said.

A successful sale of De Beers would mark a significant step forward in Wanblad’s efforts to streamline Anglo’s business and revive its fortunes after a series of missteps that left the century-old miner vulnerable to BHP’s takeover attempt.

The company has successfully spun off its platinum mining unit, and agreed in November to sell its coal business to Peabody Energy Corp. The coal deal has come into question after Peabody said a fire at one of the mines could be grounds to walk away from the purchase, while Anglo said the deal should still go ahead.

Cleaver, currently chairperson of emerald miner Gemfields Group, was CEO of De Beers until 2023. He’s in the advanced stages of arranging funding for a potential offer, two of the people said.

Penny is also a former De Beers CEO, who ran the company when the billionaire Oppenheimer family still owned a stake. He led De Beers through the global financial crisis, when it was forced to shutter mines and tap its shareholders in an emergency rights issue and is currently chairman of asset manager Ninety One.

O’Keeffe is a mining veteran who sold coal producer Riversdale Mining to Rio Tinto Group for $3.7 billion in 2011. He’s chairman of Burgundy Diamond Mines, an Australia-based company which operates the Ekati mine in Canada, once owned by BHP Group.