Derby have confirmed discussions with Turki Alalshikh's Lion Sport to buy a controlling interest in the Championship outfit will no longer proceed and that the club is now off the market.
The purchase process had been sanctioned by both the Independent Football Regulator and the EFL, notification of which the Rams received last week.
But Derby said in a statement on Monday: "Today the club received notice that Lion Sport no longer wanted to continue with the purchase.
"For the benefit of any doubt, the club is now off the market and will continue to operate under the loyal, committed and unwavering support of Clowes Developments."
Saudi government official and boxing promoter Alalshikh said in an Instagram Story: "I would like to thank everyone at Derby County Football Club, and everyone involved in this process for all their hard work over the past few months.
"We understood that the IFR process takes time and fully respect the importance of that, but unfortunately with the season already started, it would leave us with no time to prepare the team or the club for the season ahead.
"After careful consideration, we don't feel it is right to proceed at this time without the necessary preparation in place, but we will remain in conversation with the club and see what is possible in the future.
"I personally wish the team and club every success for the season ahead."
Derby begin their league campaign at Charlton on Saturday.
An IFR spokesperson said in a statement: "The IFR has a statutory duty to thoroughly test all prospective owners of a club in the top five divisions of men's football.
"The assessment was completed in 55 days out of the 90 days allowed by law. The IFR had taken a 'minded-to decision' to approve the bid before the start of the 2026/27 season. This had been communicated to all parties last week.
"In every case, we must consider a broad but fixed list of matters - all set out in statute.
"This includes assessing all candidates against the IFR's test on financial soundness, sufficient financial resources, source of wealth, and honesty and integrity - including a check on any criminal proceedings or convictions, civil actions and other regulatory investigations."