Such an outflow, if a deal goes ahead, could weaken the rand.

Anglo American was encouraged by key shareholders to continue engaging in talks with BHP over its proposed $49.18 billion mining merger.

Of the investors that Bloomberg spoke to this week, some suggested that BHP should provide a commitment to cover any lost value suffered by the subsidiaries’ new owners.

The Nisk deposit was first discovered by Inco, now Vale, in 1962.

BHP has until 16:00 GMT on Wednesday to make a binding bid for Anglo American.

LGIM is among Anglo's biggest investors with a stake of about 2%.

This will result in black investors holding a 13% interest in the company and the Bafokeng business it acquired last year.

BHP faces a critical question: what would it take to draw the smaller company to the negotiating table within the next few days?