STIM is a copyright organization and only someone who is part of the creation can register the work on STIM. Usually, your music producer, your publisher or you will take care of the STIM registration. So this would be the first choice.
However, we are a registered Publisher at STIM, but we can’t register a copyright without taking a cut because of the way STIM’s registration form is structured. So it’s a no brainer to register it yourself.
After all, the registration process is really simple.