Assuming that he owns the intellectual property--e.g. copyright and trademark in his company's name, …
There is, unfortunately, no general answer: it would be legal for you to own …
If you are not being paid for work done per an agreement, you may …
If you had obtained the domain name for them, you could likely do this. A …
The person who contracted with you for the work of improvement on the home …
Are you a lawyer?