It depends on what you mean by "fully owned by the buyer."
Software consists of at least two things
The media used to distribute software (excluding online downloadable installation techniques) are physical objects and can be owned and transferred just like any other physical things. These phyisical things an also be rented or restricted in their ownership, just like other physical things.
The code contained on the media (or distributed online or by loaned media) is not physical, but can be owned, transferred, rented or restricted in these transactions. Code is also covered by copyright or similar laws (depending on country), and there are additional rights and restrictions attached to it. These include
right to copy or prevent copying
right to distribute or prevent distributiing
right to modify or prevent modification
To answer your question it depends on what you mean when you say that the buyer owns the software. In almost all cases, buyers own the media of delivery. But ownership of the code varies greatly. Some of the common flavors are:
- Buyer owns the code completely and can do whatever she wants, including copying, distributing, modifying, etc. (this is a full transfer of copyright to buyer). The developer no longer has any rights in the code. This is probably not what you want. This could be called fully owned software
- Buyer owns a copy of the code completely and can do whatever she wants, including copying, distributing, modifying, etc. However, the software developer also still has the right to copy, sell, distribute modify, etc. (this is a full license of copyright to buyer). This is also probably not what you want. This could be called fully licensed software
- Buyer owns a copy of the software and may use the software however she chooses personally or within her organization, but is restricted in copying (maybe a backup copy is allowed). Redistribution of the one copy outside her home or organization and modification may or may not be allowed. This approach may be called software as product or shrinkwrap software as described in other answers. Note that shrink wrapped also implies that the software is standardized (not customized) and that the rights (the contract) are pre-bundled and not negotiated by the buyer.
- Buyer owns a copy of the software for use on only one machine, but is restricted in copying (maybe a backup copy is allowed). Redistribution of the one copy and modification may or may not be allowed. This can also be called software as product or shrink-wrapped software.
There are numerous variations on these themes.
SUPPLEMENT: To indicate that the licensed versions of these arrangements (2. through 4.) are unlimited in time (not a service-for-a-period), the term fully-paid or fully-paid-up is often added to the term license or software.