The former Rangers Football Club has won an appeal against a tax bill over its use of Employee Benefit Trusts.
The club, which is now in liquidation, used the scheme from 2001 to 2010 to make £47.65m in payments to players and staff in the form of tax-free loans.
HM Revenue and Customs (HMRC) had challenged the payments, arguing that they were illegal.
Rangers disputed the bill and a First Tier Tax Tribunal (FTT) has ruled the payments were loans that can be repaid.
The decision was welcomed by Murray International Holdings, who were majority shareholders of the old club until Craig Whyte's takeover in May 2011.
However, HMRC said it was considering an appeal.
Liquidators BDO said they were reviewing the tribunal's decision closely.
Rangers chief executive Charles Green said the verdict in the so-called Big Tax Case "undermines the validity" of a Scottish Premier League investigation into alleged undisclosed payments to players.
In its ruling - which was endorsed by two judges, with one dissenting - the FTT said the lengthy appeal had been heard over 29 days.
"At a late stage in its deliberations it became clear that the tribunal would be unable to issue a unanimous decision. It is conscious of and regrets the consequent delay," it said.
"The majority view reflects the argument that the controversial monies received by the employees were not paid to them as their absolute entitlement.
"The legal effect of the trust/loan structure is sufficient to preclude this. Thus the payments are loans, not earnings, and so are recoverable from the employee or his estate."
The dissenting opinion came from Dr Heidi Poon, who concluded that the money received by the employees through the trust constituted earnings for income tax purposes.
The tribunal agreed to a request to anonymise the published form of the decision.
In a statement, Murray International Holdings said: "We are satisfied that the tax tribunal has now published its widely awaited decision and note the contents thereof.
"We are pleased with the judgement which leaves minimal tax liability and overwhelmingly supports the views collectively and consistently held by our advisers, legal counsel and MIH itself.
"This has been an exceptionally long, difficult and expensive process involving not just the tax tribunal but also significant efforts to resolve the matter with senior HMRC officials on a commercially sensible basis for all parties.
"We will therefore review the detailed content of the decision with our advisers and legal counsel to ascertain what action, if any, is now required by MIH."
The MIH spokesman said that while the company had "respected the privacy" of the tribunal proceedings, "a substantial quantity of confidential information" about the case had made its way into the public domain stimulating "often ill-informed debate".
The statement continued: "This has been wholly inappropriate and outwith the fundamental principles of natural justice.
"We therefore formally request that the relevant authorities investigate how these sensitive details have been released so widely.
"We have instructed our lawyers to retrospectively review online and printed publications relating to the case to identify whether legal redress is either appropriate or necessary."
A spokesman for HMRC said: "We are disappointed that we have lost this stage of the court process and we are considering an appeal.
"The decision was not unanimous and the diligence of HMRC investigators was acknowledged by the whole tribunal.
"HMRC is committed to tackling avoidance and it is right that we challenge the type of avoidance seen in this case."
A statement from BDO said: "The joint interim liquidators are reviewing the tribunal's decision closely so as to determine the impact on the liquidation of RFC 2012 Plc.
"We are unable to provide further comment at this time."
The former lawyer who advised Rangers on how to set up Employee Benefit Trusts, Paul Baxendale-Walker, welcomed the tribunal's ruling.
He said: "This was tax planning which any taxpayer - rich or poor - can use. We now know that it was legal and effective. HMRC will now have to answer some very hard questions."
BBC Scotland's business correspondent David Henderson said the implications of the tax ruling were that "all those footballers who were playing for Rangers, happily being paid using these EBTs, may well get a letter in the post soon, saying 'give the money back to the liquidators, for onward transfer to the creditors'."
"That could include Sir David Murray, who allegedly took about £6m through this scheme."
He said that while HMRC has lost its principal claim, because it is a creditor of Rangers, it may now recover other taxes it was not paid as the club collapsed, as a result of this latest ruling.
Old Rangers was under the control of Sir David Murray when it began using EBTs.
He sold the club for £1 to Scottish businessman Craig Whyte in 2011, while the tax liability was in dispute.
But Neil Patey, a partner at Ernst and Young, does not think former players and staff will necessarily have to return money they received.
He told BBC Radio Scotland: "The loans are repayable at some point during the lifetime or maybe even at death, from the estate. But that is between the trust and individuals.
"That will be at some point in the future, which is at the discretion of the trustee, in effect."
The FTT, before three judges, concluded in January, one month before the old Rangers, now under the control of Mr Whyte, was forced into administration by HM Revenue and Customs (HMRC) over non-payment of tax totalling about £14m.
HMRC subsequently rejected proposals for a creditors agreement that would have allowed the old club to continue.
Administrators Duff and Phelps then negotiated a sale of assets to a consortium led by Charles Green for £5.5m.
He has since formed a new club, now playing in the Scottish Football League Third Division.
In a statement released in response to the tax case ruling he said: "The judgment will not affect the operations of the club nor the proposed flotation of the business as a public company.
"This case is historic and was a matter for The Rangers Football Club plc ('oldco') which is in liquidation.
He added: "The judgment serves to further undermine the validity of the SPL Commission into the use of EBTs.
"As we have said all along the SPL decision to press ahead with a commission was ill-timed and fundamentally misconceived."
UPDATE: An appeal to the BBC Trust about the terminology used in this story was partially upheld on 18 June 2013.