Every producer starts in the same place: 100% ownership of their composition.
The real question isn’t ownership it’s administration. You can go the DIY route and register with ASCAP or BMI, The MLC, HFA, and various foreign societies yourself. You’ll keep 100% of what you collect, but you’re responsible for all registrations, tracking, international affiliations, and fixing royalty mismatches. That means 100% money, but also 100% labor and potential “black box” revenue if something slips through.
The alternative is using a publishing administrator. You still retain 100% copyright ownership, but instead of managing multiple entities, you get a single dashboard and global administration that collects mechanical and publisher shares worldwide. There’s a setup fee and commission, but you’re trading margin for infrastructure and infrastructure often means higher total capture across territories.
When I started, I was doing the DIY, but now it's easier to use an administrator (we use Songtrust currently). You'll still need to register with a PRO, but the administrator works with the PRO to make the process somewhat smoother. If you’re serious about building catalog income instead of leaving money uncollected, proper publishing registration is not optional. It’s foundational. If you haven’t set yours up yet, this is step one.