RANGERS' administrators last night blamed proposed changes to the sporting and financial sanctions for Scottish Premier League clubs affected by "insolvency events" for the delay in naming their preferred bidder in the sale of the club.

Duff & Phelps had hoped to yesterday name and grant a period of exclusivity to one of three parties to have tabled an offer – the Blue Knights, Bill Miller, and an Asian consortium – but a statement from the SPL that its clubs would discuss amending the penalty for clubs in administration, as well as possible sanctions for "newcos", has led to the administrators holding off on an announcement until they have discussed the matter further with potential buyers.

If proposals revealed yesterday by the SPL are adopted at a meeting on April 30, any new company inheriting the share in the SPL from a liquidated club would face a deduction of 10 points for two successive seasons, and would also have its revenue from the SPL reduced by 75% for three successive seasons.

For clubs who go into administration, the penalty could be increased from 10 points, as is the current ruling, to the greater of 15 points and a third of the club's points total in the preceding season. Eight votes are needed for the sporting sanctions to be adopted, and 11 for the financial penalty for "newcos" to pass through. If adopted, the amendments will take effect from May 14, the day after the final day of this season.

This latest development has frustrated the Rangers administrators. "As administrators, we had hoped to announce [yesterday] the acceptance in principle of an offer for the purchase of Rangers Football Club, which would be followed by a period of exclusivity while due diligence is undertaken," said Paul Clark, one of the administrators handling Rangers' case.

"Regrettably, this is not now possible as we were informed over the Easter holiday period that the SPL is proposing to consider at a general meeting on April 30, significant rule changes in relation to clubs which find themselves in an insolvency situation.

"The effect of such revised measures being considered at this juncture is that we, as administrators, are duty bound to inform those parties who have submitted bids of