Commodities trader Glencore has officially confirmed the terms of an improved merger offer to mining group Xstrata.
Glencore has offered just over three of its shares for each Xstrata share, up from its original offer of 2.8 shares which valued the company at $US90 billion.
Some Xstrata shareholders are unhappy with the revised terms which include generous retention bonuses for key members of the Xstrata team.
Glencore says it's the final offer.
But Fat Prophets fund management head Rupert Nathan says it's not enough for Qatar Holdings, which owns 12% of Xstrata.
He also says the drawn-out negotiations indicate both sides believe the commodities super cycle is not over yet.