If you haven’t been following this story closely, BHP’s takeover offer for Anglo American last night is the third time the mining giant has lobbed in a bid for its rival in the past month.

(To make things easier, we’ll call it “Anglo” from here on out.)

BHP had been hoping third time was the charm to get Anglo’s board across the line, but it’s clear the miner still has its reservations about the deal, so turned it down once more.

However, it isn’t cold hard cash that’s failed to convince Anglo — analysts say it’s actually got to do with BHP’s proposed structure for the company, and Anglo’s businesses in South Africa.

The latest deal BHP lobbed for Anglo involved an offer of 29.34 pounds per share (up from its initial 25.08 pounds/share offer) but is conditional on Anglo unbundling its platinum and iron ore assets in South Africa.

That’s the part that has concerned Anglo chair Stuart Chambers, who said that unbundling process could take around 18 months — which is the same time frame that Anglo expects to have finished its own restructuring.

“[The proposal] consequently has the potential for material value leakage to be disproportionately suffered by Anglo American’s shareholders,” Chambers said.

According to analysts, it’s the structure that will make or break a future takeover offer from BHP.

“The conclusion here appears to be clear — this new proposal was rejected by Anglo on grounds of structure rather than price,” said Mark Kelly at MKP Advisors.

That said, Nicholas Stein from Coronation Fund Managers, which is a top-20 shareholder in Anglo, said “investors are skeptical the BHP deal is enough to get it over the line“.

BHP has said the ratio of shares it’s offering Anglo shareholders is “final”, unless there is an offer from a third party or if the board of Anglo is “minded to recommend an offer on better terms”.

“None of the conditions have been met at this point in time, and this has to be considered the ‘Final Ratio’,” RBC Capital Markets analyst Kaan Peker said.

However, he added that it may mean BHP can make a supplementary cash offer.

Will that happen? We’ll have to wait and see, with the deadline extended for another week.