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.

The Importance Of Having Music Contracts
The reasons you need to use Music Contracts. Protect yourself by having a solid agreement.

