In the absence of an agreement to the contrary, copyright in a musical work is usually first owned by the composer of that work. There are certain exceptions to this rule, and if you are uncertain, you should always seek legal advice. In practice, composers often assign or license their rights to third parties who then manage and exploit these rights on their behalf. Reproduction and publication rights are usually managed by a publisher, and communication and performance rights are usually assigned to APRA, which then manages these rights on behalf of its members.