Net publisher's share is, in the music industry, the amount of royalties received by a music publisher less any amounts of those royalties that have to be paid to writers, performers and anyone else who receives a share of royalties.
Net publisher's share can be useful in valuation as it is an indication of how big a music publisher is. The is similar to valuing a company on a revenue multiple such as EV/sales.
It is usually preferable to use profit multiples rather than revenue multiples, and net publisher's share is a modified revenue number. It is also not a number that is always disclosed. In addition, music publishing is usually part of a larger music business (e.g. recorded music sales).