The boards of Xstrata and Glencore were locked in meetings last night as they sought to finalise the details of their planned $80bn (£49bn) merger ahead of Monday morning's deadline.
Although the mining and commodities trading giants have yet to agree a transaction, analysts took the meeting as a sign that they were determined to strike a deal, ending a saga that has dragged on for months.
The discussions centre on Glencore's revised offer for Xstrata earlier this month, which it made after key shareholders such as Qatar indicated that its initial offer was too low.
Glencore's latest offer would give Xstrata shareholders 3.05 of its shares for each of theirs – up from the initial ratio of 2.8. However, a condition of the revised offer stipulated that Glencore's chief executive Ivan Glasenberg would run the enlarged group instead of Xstrata boss Mick Davis, who had previously been lined up.
Xstrata management, which had recommended the previous offer, withdrew their support to consider the ramifications of the new terms. The Takeover Panel has given them until 7am on Monday morning to make a formal announcement on the matter.
The revised offer also changed the deal from a so-called merger-of-equals to a straightforward takeover, meaning it now only requires the backing of 50.1 per cent of its shareholders, as opposed to 75 per cent under the previous proposal.
Since Glencore has a 34 per cent stake in Xstrata the new deal structure significantly increases its chance of success.
Glencore, Xstrata and Qatar declined to comment on any talks relating to the proposed deal.
Sources were split on whether Xstrata would make its formal announcement today, or wait until Monday morning.
Opinion is also divided on whether a deal will be agreed, although analysts are leaning towards a recommendation from Xstrata.
This week, UBS issued a note predicting there is a "60 per cent-plus probability that the merger will happen".