Birmingham have terminated discussions with Carson Yeung's investment company, Grandtop International Holdings, regarding a possible takeover.
Yeung is Birmingham's largest single shareholder
Hong Kong businessman Yeung, whose company had bought a 29.9% stake in July, had been set a deadline of 21 December to complete a buy-out.
But Birmingham told the Stock Exchange that the Yeung talks were over.
Birmingham have ruled out the prospect of the club being taken over until next summer at the earliest.
"The company announces that it has terminated discussions with Grandtop International Holdings as the directors are no longer confident that GIH will be able to make a general offer for the company," said a Birmingham statement.
"The directors confirm that they are not in discussions with any other potential offerors for the company."
Grandtop International chief Sammy Yu confirmed on Friday that the company had decided to "temporarily shelve the takeover plan".
He claimed: "Money is not the biggest problem - it's (the club's) attitude that makes this deal difficult to do. We want to buy this football club." Last month, co-owners David Sullivan and David Gold expressed doubts that Yeung's takeover would be completed.
Sullivan and Gold are now set to run the club as before, with Gold downplaying reported interest from Russian billionaire Vagit Alekperov.
"We have been making contingency plans that the takeover would fail for several weeks and myself and David Sullivan have been running the club on that basis," said Gold.
"Of course, there was always the chance someone could walk into our offices on 21 December with the money to buy the club.
"But in reality we have been saying for some time that the deal was dead in the water to all intents and purposes.
"The silence has been deafening from Hong Kong. Our dealings with Carson Yeung have been very brief. The takeover became an irritation we wanted cleared up."
Birmingham were the authors of their own misfortune
BBC Radio 5 Live's Pat Murphy
And Gold expressed his determination to stay involved with the club.
"I feel revitalised and rechallenged now," he said. "The future strikes me as exciting for Birmingham. There is a new manager in place, a new era and I want to be part of it."
The protracted negotiations with Yeung were one of the reasons behind manager Steve Bruce's departure to Wigan in November.
Bruce was unhappy that Yeung's consortium would not discuss a new contract with him.
"Birmingham City have got their retaliation in first and told Carson Yeung to take a hike before the deadline for his proposed offer ran out at midnight on Friday," said BBC Radio 5 Live's Pat Murphy.
"So ends a damaging five months for the club. A period of instability, during which they lost manager Steve Bruce and his assistant Eric Black while Yeung remained enigmatic about his plans to the extent Birmingham were the authors of their own misfortune.
"The board chose to sell 29.9% in return for £15m, trusting Yeung to raise another £35m in due course instead of inviting an offer for the whole company.
"David Gold says no other negotiations with any other company will start until next summer while Yeung will be looking to sell his shares back to the club.
"At today's rate, he faces a loss of £6m - a high price for his vanity purchase last summer."