American businessman Kirchner remains Quantuma's preferred bidder.

But they are "conscious of heightening anxiety and levels of interest" following reports of other bidders.

The fact that Derby's Pride Park is still owned by former owner Mel Morris has been a sticking point, with Derby City Council also working on a deal to buy the ground to help bring the Rams out of administration.

Quantuma said most of the outstanding issues delaying the takeover had now been worked through with Kirchner and that they believed than an agreement over the stadium was close.

"We consider that matters can be resolved in a short period of time and are grateful for the assistance of all stakeholders relating to the stadium," a statement from Quantuma said.

"It should be noted that the company that owns the stadium is not in administration and therefore out of our control. We have therefore extended the period of exclusivity to midnight on Saturday, 14 May."

The statement added: "For the avoidance of doubt, Mr Morris has been fully co-operative throughout the administration and has not changed his stance on the disposal of the stadium.

"He shares everyone's desire that the successful acquirer will take the club forward and understands that the acquirer will want the stadium matter resolved as soon as possible."

'It is not helpful for Mel Morris to be receiving personal threats'

Derby were docked 21 points over the course of the season for going into administration and breaches of EFL financial rules, which contributed to the club being relegated from the Championship and into the third tier for the first time since 1986.

That, coupled with the protracted nature of the takeover, has contributed to ill feeling towards former owner Morris, who has been the recipient of threatening messages.

"It is not helpful for Mr Morris to be receiving personal threats against himself or members of his family, which have caused him and his family substantial anguish and could result in a very unnecessary and serious distraction," added the Quantuma statement.

"We should be grateful if supporters and other parties could refrain from passing comments of such nature and any such threats reported to the administrators will be taken very seriously."

Derby takeover 'moving to the end game'

Analysis - BBC Sport's Simon Stone

The fact Chris Kirchner has flown to Bangkok to fulfil a prior commitment suggests he either shares the administrators' confidence about the situation being sorted out - or that there is no more he can do.

And the stated wish for the abuse against Morris to stop signifies an intent from the people still running Derby to be left clear of outside interference.

We are certainly moving to the end game now, though.

With no more matches this season, Derby have no opportunity to raise significant funds before wages are due later in the month.

One way or another, there has to be some clarity over the club's future when it reaches that point as borrowing more - as the administrators have done during this process - seems a non-starter.

Until that is received, Derby fans will continue to worry about the future.