Rangers have announced that the club's director of sports development, Craig Mather, will become interim chief executive.
Mather, a shareholder at Rangers, will act as a temporary replacement for Charles Green, who resigned last week.
In a statement to the London Stock Exchange, the club said: "Rangers announces that the Board has appointed Craig Mather, aged 42, to the role of chief operating officer for the group. In addition, Craig will act as interim chief executive officer and will be a member of the board as the interim chief executive officer.
"In the meanwhile, the search for a permanent replacement for Charles Green will continue and a further announcement will be made as appropriate."
Rangers chairman Malcolm Murray told the club's official website: "We are very pleased to announce the appointment of Craig Mather as chief operating officer of Rangers. He will also be acting chief executive which will allow us some time to examine the credentials of candidates for this position on a permanent basis.
"Craig's appointment as chief operating officer will allow the company and the club to keep moving forward. Craig has invested £1 million of his own money in the club and is committed to playing an active part in delivering future success for Rangers.
"The board has approved his appointment and look forward to him pushing us in the correct direction. Craig will lead the business on a day-to-day basis but I want to make it clear we are in a healthy position financially following the successful flotation of the company in December last year. I would also like to assure all of the supporters that this money is being used for the benefit of the club and nothing or no one else.
"The board has also instructed the law firm Pinsent Masons to conduct the investigation into alleged links between Craig Whyte and former and current personnel at the club. This process will be completed as swiftly as possible and no-one should jump to conclusions regarding the outcome.
"The fans deserve to be reassured on clarity, transparency, asset ownership and this is the main purpose of the inquiry. The last week or so has been turbulent for the club but we should bear in mind that the process of rebuilding is well underway.
"Now is the time to move forward and the most important thing for all Rangers fans, myself included, is ensuring our club can play as constructive a part in Scottish football as possible."
Information from the Press Association was used in this report