Clients are usually intrested in what the software will do for their operation. Clients are paying for a service, not investing in a software company.

>>Without a signed agreement, ownership of the copyright defaults to the author.
>>
>>>>With custom made applications who owns the copyright, the software developer or the entity who paid for such software to be developed. Is there any difference with general software applications and custom made ones with regards to who owns the copyright?
>>>
>>>Everything depend on contract agreement.
>>>Usually copyrights are ownership of investor who pay development of the software.
>
>I am wondered, which investor will fully pay development of the some software product without the ownership of the copyright?
>If this is possible in USA, I will be glad to work for any american investor as a contractor or consultant.