It further warns that if the 19m share offering is unsuccessful it would put the financial future of the club into fresh uncertainty, two-and-a-half years after the previous operating company fell into administration.
The Rangers International Football Club plc board, in a statement announcing the new share issue, also admit that if they only sell the minimum level of shares set at 15 million, further working capital will be needed "towards the end" of this year. But they said "there can be no certainty that such funding will be available".
In their April business review, Rangers said they might issue shares if season ticket sales were "materially less than anticipated".
The board was concerned that a move by Union of Fans, assisted by former Rangers director David King, to pool season ticket money this summer over concerns regarding the security of Ibrox and Murray Park, might hurt the club. In March, Rangers chairman David Somers admitted that "material uncertainty" over season ticket income may cast doubt about the club's ability to continue as a going concern.
Sales of season tickets sat at just over 23,000 according to the latest statement. But Rangers previously sold 38,000 season tickets for the 2013/14 season.
Attendences at Ibrox, a valuable income stream, have dropped. Only 31,175 turned up to see Rangers beat Dumbarton 4-1 in the Scottish Championship. A game against East Fife at the same time last year drew 42,870.
But the new share issue is just the start. The board said: "Assuming full subscription, the company will require additional external funding in the latter half of the current financial year." And in a statement to the stock market, revealing the bid for a new share issue, RIFC plc said the club was targeting a return to the top of Scottish football within three seasons, and UEFA competition thereafter. It confirmed it would be looking to raise up to £30m over the next three years. The board said "this will require continued investment in the playing squad over the next three years and beyond to drive on-field success."
The club admitted funds raised in the share offer would be used to repay a £1.5m loan from shareholders Sandy Easdale and George Letham, due on Monday.
On March 31, the RIFC plc had just £3.5million cash, despite bringing in £22 million in an initial public offering (IPO) share issue just over a year earlier.
But as season ticket money started coming in the cash balance at June 30 had risen by just over £700,000. RIFC plc statements show that included in the cash balance is £2.72 million relating to Rangers Retail Ltd, which is not immediately available as working capital.
As part of his 120-day review published in April, chief executive Graham Wallace said he would look at a new rights issue later in the year "when the climate will be better".
He also revealed that since the club assets were bought by the newco they had burned through almost £70m in 18 months.
The directors said: "The board acknowledges the importance of supporters as shareholders as well as its institutional investors; the open offer gives smaller shareholders the opportunity to participate in the fundraising."
They added: "The funds raised should enable the company to progress the issues identified in the business review."