The League One champions have announced losses for the seven months to December 31 of £3.7million - an improvement of 50 per cent on the same period 12 months earlier.
But Neil Patey, a partner at Ernst and Young, says the figures are not improving quickly enough to suggest boss Ally McCoist will be able to spend the sums needed to take on Neil Lennon's new Scottish Premiership champions if they win promotion back to the top-flight at the end of next season.
He said: "The club have improved revenue and cut costs so they are heading in the right direction, but there is some way to go before they achieve break-even.
"Rangers are now heading up the leagues which will bring in extra revenue for things like increased season-ticket fees, prize money and possibly European football once they are in the top flight, but they are not at the stage yet where they can stop relying on external injections of cash.
"There needs to be further cost-cutting and Graham Wallace's 120-day review should deal with that. However, for Rangers to get to break-even before they return to the Premiership would be a big challenge.
"Unless they get an external equity injection, the fact is Rangers will not be able to compete financially with Celtic until they get back into the Champions League.
"How much will it take? It's difficult to say but Celtic have been pulling in £10million to £15million from Europe for the last couple of years, so that gives you an idea kind of money Rangers are missing out on. It will require tens of millions, for sure."
Rangers fans, angered by the current board's management of the club, are pressing ahead with a trust fund that will collect season-ticket cash and only hand it over to the club once they have been given security over Ibrox and Murray Park.
But both chairman David Somers and auditors from Deloitte have warned that could put the club's status as a going concern in jeopardy.
"The warning in the accounts report appears to be genuine," said Patey. "Deloitte wouldn't scaremonger, they just do their job. They have raised the fact their is a material uncertainty because they think the fans season-ticket trust plan will have a serious impact.
"Scottish clubs especially rely on on ticket sales and if they don't receive that money then there is a serious short-fall of cash.
"Now we're not sure if the fans' plan will put the club on life support just yet but it could have serious financial consequences if the club don't get the money though."