Rangers made an operating loss of £8.3million last season and need to recoup those losses in the next 12 months, the club revealed in their annual accounts.
The figure was an improvement on the previous 12 months, which saw a £14.4million loss.
The club - who host Kilmarnock in the Scottish Cup fourth round on Sunday - recently secured a £3million loan from shareholder Mike Ashley but the report warned they would need an extra £8million investment in the next 12 months.
Rangers expect promotion to the top flight this season, and consequent uplift in season ticket income and other revenue in the summer.
Ally McCoist's team fell nine points behind Scottish Championship leaders Hearts last weekend, but there is the opportunity of progressing through play-offs if they were to miss out on the title.
The accounts showed that total revenue was up almost a third to £25.2million with retail revenue almost quadrupling to £7.6million. Sponsorship and advertising revenues nearly doubled to £1.5million.
But the continuing need for cash places an ongoing question mark over the club's finances, despite Rangers also taking in more than £3million in a share offer this season.
Staffing costs fell by more than £3million to £14.7million but these savings were wiped out by an increase in "operating charges", which rose to £16.4million.
Former Rangers owner Craig Whyte has been arrested in the UK following his detention by police in Mexico.
An arrest warrant was issued a fortnight ago for the 43-year-old in connection with an investigation into the sale of Rangers in 2011.
Whyte took control of the Ibrox club in May 2011 but it went into administration in February the following year.
It is understood he was held by police in Mexico on Wednesday and flown to Heathrow yesterday, where he was detained by Police Scotland officers.
He is expected to appear in court today.
A Crown Office spokesman said: "We can confirm a 43-year-old man is in custody and is expected to appear at Glasgow Sheriff Court."
"As proceedings are active and subject to contempt, it would not be appropriate to comment further."
Four men appeared in court earlier this month charged with fraudulent activity linked to the sale of the club three years ago.
Gary Withey, 50, David Whitehouse, 49, Paul Clark, 50, and David Grier, 53, all made no plea or declaration and were granted bail following a hearing at Glasgow Sheriff Court.