Music ownership databases are lists of the owners of compositions and the people who represent them. Often, a piece of music will have more than one owner. This is caused by Publishing contracts, co-writing, band contracts, label deals, and similar music contracts. Music ownership databases are created from the idea that with more transparency about the owners of musical compositions, the lower the costs become to create and use music. For example, a derivative license is needed when a portion of a piece of music is used in a different piece, which is a common practice in hip hop music, among other genres. In American copyright laws, a derivative work must have permission from every owner of the original work. If it is not known who the original owner of the work was and artists use it any