In a series of e-mails sent to agencies, the broadcaster informed TV buyers that it had a "couple of issues regarding delivering deals in February" and it expected to under-deliver campaigns by up to 5%.
However, its position in delivering campaigns that target an upmarket audience involves a predicted shortfall of 8% against agency plans.
The broadcaster claims that this is owing to an increase in demand in the month for this audience. However, it expects its ABC1 impacts to have fallen by nearly 7% on last year.
Jonathan Allan, the sales director of Channel 4, said the e-mails were part of its bid to work more transparently. He said: "We decided to write to agencies to be a bit more on the front foot."
Channel 4 will look to improve its audience performance in order to claw back the deal debt to avoid having to roll it over to next year or, in the worst-case scenario, pay agencies back.
The chief executive of Channel 4, David Abraham, recently admitted that the company would report its first loss for more than a decade for 2012 but that this was planned and it would invest more in programming.
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