You have the session booked. The collaborators are lined up. Someone brings a hook, someone else brings a chord progression, and by the end of the day you have a song. Then comes the part that songwriters consistently underestimate: who owns what, and what needs to happen on paper before the royalties start flowing.
This article covers the mechanics of co-write splits: what U.S. copyright law says about joint authorship by default, how PROs structure performance royalty distributions, what documentation is required when shares need to change, and how The MLC ties your registration to digital mechanical royalty payments.
This is not legal advice. For agreements that involve significant ownership stakes or publishing deals, consult an attorney with music industry experience. This is an explanation of how the systems work.
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#### What U.S. Copyright Law Says About Joint Authorship
Before you think about PROs or royalty splits, the foundational issue is copyright ownership itself. U.S. Copyright Office Circular 14 explains that the authors of a joint work are co-owners of the copyright in the work. Each co-author holds an equal undivided interest in the whole work.
That default, equal and undivided, applies regardless of how much each person contributed unless the parties have agreed otherwise in writing.
In practice, this means that if two writers collaborate on a song and sign nothing, both hold a 50/50 interest by operation of law. If three writers collaborate without a written agreement, each holds a one-third interest. The written split agreement is the mechanism by which you depart from that default and document a different arrangement.
The earlier you have that conversation and commit it to writing, the cleaner the ownership record.
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#### The Basic PRO Structure: Writer Share and Publisher Share
When a song generates performance royalties, from radio play, streaming, live performance, and other licensed uses, performing rights organizations collect and distribute those royalties.
According to BMI's official FAQ, BMI designates one half of royalties for the songwriter or composer, and one half for the publisher or copyright holder.
ASCAP operates on the same structural principle: royalties are allocated between writer shares and publisher shares. According to ASCAP's royalty payment information, ASCAP distributes separately to writers and publishers affiliated with the work.
On a co-write, the writer share is divided among the songwriters according to the agreed splits. The publisher share is divided among the publishers associated with those songwriters.
If you do not have a publisher, BMI says you will receive the publisher's share as the writer. In that case, BMI may show "Manuscript" as a publishing placeholder, which indicates that writer and publisher shares are flowing directly to the writers.
For a deeper explanation of what publishing means in this context, see /definitions/.
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#### The Co-Write Split Conversation
The split conversation is most productive before recording begins, and certainly before either party registers the work with a PRO or The MLC. Here is why: changing splits after a work is registered requires documentation and a formal update request. Agreeing before registration is administratively cleaner.
A co-write split covers at minimum:
- What percentage of the writer share each collaborator receives
- What publisher or publishing administrator is associated with each writer
- Whether any collaborator is contributing a pre-existing sample, interpolation, or hook that changes the ownership math
The specific form of that agreement varies. Some collaborators use formal split sheets; others use email confirmations or contracts prepared by their attorneys. The point is that the agreement exists in writing and all parties have signed or otherwise confirmed it.
The copyright default under Circular 14 is equal and undivided. If the actual split is different, 70/30, 60/20/20, any other arrangement, you need a written record of that agreement.
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#### When Splits Need to Change: What BMI Requires
If a registered work needs a share update, because an original split agreement was entered incorrectly or a new arrangement has been reached, BMI has a defined process.
According to BMI's instructions for updating registered works, you should not submit a new work registration to correct information on an existing work. You submit an update request.
When an update request would reduce or remove a BMI licensed composer, author, or publisher share, supporting documentation is required. BMI accepts signed contracts (including administration agreements, sub-publishing agreements, and assignments), court orders, signed settlement agreements, signed stipulations, written acknowledgments by all parties, declarations made under penalty of perjury, and notarized affidavits.
BMI also recommends submitting a letter of direction signed by all parties agreeing to the proposed changes. Any missing information can delay processing.
The practical implication: if you and a co-writer later disagree about what was agreed, and one of you wants to change the registered splits, BMI will require documentation that supports that change. A contemporaneous written agreement signed at the time of the session is cleaner evidence than a disputed recollection.
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#### The MLC and Digital Mechanical Royalties
Performance royalties handled by BMI and ASCAP are one revenue stream. Mechanical royalties are a separate stream, covering the reproduction of a song in recorded form. For digital audio, streaming and download services operating in the United States, mechanical royalties flow through The Mechanical Licensing Collective.
According to The MLC's explanation of how it works, DSPs operating under the blanket license send usage data and royalties to The MLC each month. The MLC then matches those DSP-reported streams and downloads to the songs registered by members and calculates the royalties owed. Royalties are distributed to members on a monthly basis.
The key requirement: your work must be registered. The MLC's work registration page describes three methods: individual work registration in the Member Hub, bulk registration via a template upload, and submission of a Common Works Registration file for large catalogs.
If your song is not registered with The MLC, the matching process cannot link DSP-reported streams to your work. Royalties for unmatched works are held in a pool and distributed according to The MLC's procedures, but active registration is how you make a direct claim.
For a full explanation of The MLC and how it fits into the broader mechanical licensing landscape, see the FTSMusic article on The Mechanical Licensing Collective.
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#### What a Complete Pre-Session Splits Conversation Covers
You do not need a lawyer in the room to have this conversation. You do need the conversation.
Before the record button: agree on percentages for each writer. Note that the copyright default under Circular 14 is equal shares unless you agree otherwise in writing. Agree on what publishing entity or administrator is attached to each writer. If anyone is bringing in a pre-existing element that changes the composition ownership, acknowledge that explicitly. Write it down, confirm it in writing with all parties, and keep a copy.
After the session: register the work with your PRO and with The MLC using the agreed splits. BMI and ASCAP registrations handle performance royalties. The MLC registration handles digital audio mechanical royalties. Both are required. Neither substitutes for the other.
The split conversation is not a bureaucratic formality. It is the point at which the ownership of a song becomes defined. Unclear splits do not stay theoretical, they surface when royalties arrive and the numbers do not match someone's expectations.
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#### Internal Reference: Key Definitions
- Publishing: See /definitions/#publishing
- Mechanical royalties: See /definitions/#mechanical-royalties
- Performance royalties: See /definitions/#performance-royalties
For context on how ASCAP and BMI operate, see What ASCAP and BMI Actually Do.
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More from the Indie Label / Artist Dev desk →Frequently asked
What does U.S. copyright law say about co-authorship default ownership?
U.S. Copyright Office Circular 14 explains that the authors of a joint work are co-owners of the copyright in the work. Each co-author holds an equal undivided interest in the whole work unless the parties have agreed in writing to a different arrangement. This means that without a written split agreement, co-authors have equal shares by default regardless of individual contribution.
What is the standard BMI split between songwriters and publishers?
According to BMI's official FAQ, one half of royalties goes to the songwriter or composer, and one half goes to the publisher or copyright holder. On a co-write, the writer share is divided among the songwriters per the agreed splits.
What happens if I do not have a publisher?
BMI says that if you do not have a publisher, you will receive the publisher's share as a writer. BMI may show Manuscript as a placeholder, meaning writer and publisher shares flow directly to the writers.
Can I change the splits on a work already registered with BMI?
Yes, through a work update request. If the change would reduce or remove a BMI licensed composer, author, or publisher share, supporting documentation is required. BMI accepts signed contracts, court orders, signed settlement agreements, and other forms of written agreement.
How does The MLC know which songs to pay royalties for?
The MLC matches DSP-reported streams and downloads to songs registered by members. If your work is not registered, it cannot be directly matched. Registration through the Member Hub is the standard method for individual works.
Do I need to register separately with The MLC and my PRO?
Yes. BMI and ASCAP handle performance royalties. The MLC handles digital audio mechanical royalties. They are separate systems covering separate revenue streams, and registration with one does not substitute for registration with the other.
Further reading on From The Stem
· Publishing definition
· Mechanical royalties definition
· Performance royalties definition
· What ASCAP and BMI actually do
· The Mechanical Licensing Collective explained