A co-publishing agreement means that while the music publisher has ownership in the copyright and administers its exploitation, another publisher (possibly a songwriter’s own company) controls the other piece of the publisher’s share of ownership. This type of agreement often happens when established songwriters who have a lot of power within the industry establish their own publishing entity and enter in an agreement with another publisher.

Making Your Own Music: Songwriting Basics
Songwriting is an excellent way to express your thoughts and feelings and to communicate them to your friends and family, even if you have no aspirations of musical fame or fortune.
