Almost 90% of respondents to a Computer Weekly/Harvey Nash Big Question poll admit their businesses have not accounted for the coming changes in software licensing in their budget forecasts.
Microsoft recently announced that it is to adopt a subscription-based licensing model for its Office software. And IBM has changed the licensing of its S/390 mainframe software, offering workload-based licences.
Analyst firm Gartner Group predicts this will have a "dramatic impact" in the way enterprise software is licensed in the coming years, but 88% of IT managers said their companies have not considered changing at this stage.
One respondent said, "We are watching these changes with interest, but it is too early for us to say if we will want to switch to a different payment model."
Another said the licence changes were "commercially immature" and that "none of the current models suit users of any scale".