That would represent a significant increase compared to previous years, when Windows licensing costs were generally said to be raised by lower "single-digit" percentages. The Windows licensing increase thus adds another layer to what is already becoming an increasingly difficult pricing environment for OEMs. Microsoft also notes that properly licensed Windows can involve either a full operating system license or an upgrade license combined with a qualifying existing license. Enterprise licensing generally builds on a qualifying Windows Pro license rather than functioning as a standalone replacement for the underlying license. Meanwhile, the reported OEM price increase comes as the whole PC market keeps struggling, and this obviously does not help the case.