Former Ibrox director Dave King has warned that Celtic will "shoot through 10 in a row and beyond" unless Rangers secure a significant one-off investment.
King, who lost his £20million investment when Rangers went into liquidation, has held talks with current Rangers board members over putting more money in but has now declared he wants to lead a fan-based group to secure a major shareholding.
And the South Africa-based businessman urged fans to seek several guarantees from the board, financial and otherwise, before buying season tickets for next term.
The League One leaders this week secured loans totalling £1.5million from two major shareholders - Laxey Partners and Sandy Easdale.
But King feels more money is needed to give Rangers the chance to challenge Celtic, who are close to a third consecutive title, in the coming years. If it is not forthcoming, he fears a decade of dominance by Celtic.
In a statement, King said: "My assessment is that the business is not commercially sustainable in the short term and hence requires a level of soft investment.
"The board is focusing on right-sizing the business ie. cutting costs to match the income.
"It is correct that any club must, over the long term, operate within its means but in the short term Rangers needs a significant once-off financial boost that cannot be met from the current revenue stream.
"Without this we will not get back to where we should be. If we cut our costs to suit our present income we will remain a small club and Celtic will shoot through 10 in a row - and beyond - while we slug it out for the minor places.
"That is not the Rangers that I grew up with and not the Rangers that we should be passing down to our children and grandchildren.
"Such a soft investment will only come from a fan based group that regard their return as winning trophies in the top flight.
"I have been such an investor and want to be so again. I would like to lead a fan-based initiative to acquire an influential shareholding in the club."