A spokesperson for Texas-based Phillips 66 said that the sales process is ongoing, saying that it had attracted strong interest to date.
The sale will be closed if “appropriate value is achieved” and provided government approvals are received.
The Irish Examiner last week revealed that a number of firms had expressed an interest in the refinery, including Canadian company Irving Oil, private equity firm ArcLight Capital, PTF PlusOne and Valero Energy.
Family-owned Irving Oil is believed to be in pole position and remain the most likely winning bidder.
Irving’s interest in Whitegate could stem from the refinery’s potential to act as a supplier of feedstock crude oil for its other operations, according to an industry expert.
Global energy consultancy firm FGE Energy’s head of refining Steve Sawyer said keeping “feedstock costs down” could be partly behind Irving’s interest in the refinery.
“Whitegate is a very simple refinery and something like a third of its output is fuel oil.
"In a bit more detail, that’s low sulphur, straight-run residue which is a very good feedstock … and I wouldn’t be at all surprised if Irving looks to that refinery to supply some of its feedstock needs,” Mr Sawyer said.
Mr Sawyer said the rationale for Irving’s interest in the refinery was the clearest of all the companies thought to be on Phillips 66’s shortlist.
Using Whitegate to give feedstock would mean the refinery staying in operation.
Mr Sawyer warned, however, that Phillips 66 “will want the best value, not necessarily maintaining the highest number of jobs, unfortunately”.
A spokesperson for P66 declined to comment when asked if a commitment had been sought from potential bidders that the refinery would remain operational and jobs maintained as part of any deal.
About 160 employees and a further 130 contractors are employed at Whitegate.
The other most likely option for the future of Whitegate is to close the facility and use it as a storage terminal which would result in the loss of most if not all jobs.
Turning the refinery into a biodiesel plant as has happened elsewhere across Europe could be another way of ensuring Whitegate’s future but this seems unlikely given the shortlist of interested parties.
“I must admit, another option for me [is] whether the facilities there could be turned into a biodiesel operation a bit like Total are doing to some of their refineries in Europe; turning them into a biodiesel operation in Europe,” the FGE analyst said.
French oil company, Total, Europe’s biggest refiner, last year announced its intention to convert its La Mede refinery into a biorefinery as part of a €200m investment.
Mr Sawyer said that none of the parties understood to be interested in Whitegate has a track record in such transformations, however, and added that it would “be an entirely new venture” for them.
The refinery has been on the market since November 2015 when Phillips 66 again decided to seek a buyer having pulled the plug on an earlier sales process the previous year due to a lack of interest.