Clark has been forced to operate on the tightest of budgets since taking over in the summer of 2012 due to the Championship club's ongoing financial struggles.
Prized assets such as Jack Butland, Curtis Davies and Nathan Redmond have all been offloaded to raise much-needed funds, while the vast majority of incomings have been free transfers or loan additions.
And the only way Clark anticipates any new faces arriving at St Andrew's in January is if he can first free up funds within his squad by the way of departures.
"There'll be nothing happening," Clark said. "It'll be very similar to last January in terms of people having to be moved out before any players are brought in. That's the situation now.
"It doesn't matter if it changes because of injuries of suspensions because that's the position we're in financially. I fully understand it, I'm fully aware of it.
"So unless players can be moved on to bring other players in, we'll have to stick with what we've got."
Asked if the same applies to potential loan deals, Clark replied: "The remit whether they come in on loan, permanently or on short-term contracts is that players have to go out before any of those scenarios happen."
Birmingham are currently without a host of players due to injury heading into the hectic festive period, including Mitch Hancox, Lee Novak, David Murphy, Matt Green, Neal Eardley, Jonathan Spector and Akwasi Asante.
City lie 19th in the Championship ahead of Saturday's trip to Bournemouth.
- Jack Butland
- Nathan Redmond
- Curtis Davies