My PVM bundle (virtual machine) size is bigger than the virtual hard disk size in the configuration and Guest OS.
It happens because macOS bits calculation is 1 GB = 1000 MB, whereas Windows and most of the other OSes calculate 1 GB as 1024 MB, so does Parallels Desktop application.
As a result, the PVM size can be slightly (or even significantly) bigger, depending on the actual virtual hard disk size.
For example, if your virtual hard disk size is 50 GB, the PVM size will be nearly 3 GB more, making it 53 GB, however if the hard disk size is about 150 GB, the total PVM size will be close to 11 GB extra space on the Mac hard disk.
NOTE: having snapshots also makes PVM bundle bigger.