Birmingham chairman David Gold says the chances of prospective new owner Carson Yeung's planned takeover actually happening are now "less than 40%".
Gold and co-owner David Sullivan each own 23.22% of the Blues
Hong Kong businessman Yeung had been given until Friday to prove he could raise the £35m needed to buy out Gold and City co-owner David Sullivan.
Gold told BBC 5 Live he thought Yeung had been "messing the club around".
"We will know by 21 December if this deal has any chance of succeeding or if it's failed," Gold added.
"Today, I have to confess, I'm below 40% that the deal will go through.
We were seeing him at most games two or three months ago, now we're not
Birmingham City chairman David Gold
"As we speak we're not very optimistic that this will happen and that's why we're running the club as though we are ongoing owners."
Yeung's plan is to add to the 29.9% stake he purchased in the club in July to become the leading individual share-holder. Gold and co-owner David Sullivan still have 23.22% each.
Gold added: "We were seeing him at most games two or three months ago, now we're not.
"We've not had any communication with him for three weeks and that of course leads us all to believing that this deal is slowly disappearing."
Yeung's adviser, fomer England international Steve McManaman, told the Sunday Mirror: "The takeover is rolling along, but very slowly.
"I don't think there's much chance of being done by this month's deadline. If anything it is more likely to be done in February or March from what I have heard.
"I honestly don't know whether that will be too late for David Sullivan and the Gold brothers."
Gold insisted that new manager Alex McLeish would get their full support with funds available in the January transfer window.
"The board now have agreed that we are going to run the club as if the deal isn't going to go through," Gold told BBC Radio 5 Live. "I think it's best for Birmingham City Football Club.
"(McLeish) has got four or five weeks before the transfer window opens. As we've done in the past we will support our manager to the best of our ability."