Before I dig into this issue, let me start by saying that you should always have your attorney draft a split fee agreement for joint works, and a licensing agreement when you’re allowing others to use your copyrighted works.
But let’s review what you can do in case you didn’t go the prudent route and there are no such agreements. We’ll look at a situation I came across where three people owned the copyright. One of those people decided to distribute the work and license it to feature in a commercial. So what’s the minimum amount in royalties they have to pay to the other copyright owners?
The answer is that there’s no minimum amount in a copyright split.
Generally under copyright law, joint copyright owners are each authorized to license the work as they see fit. That means each owner can issue non-exclusive licenses to third parties on commercially reasonable terms, but must account to the co-owners for their share of the royalties received.
The exception is if there is a pre-existing agreement between the co-owners, in which case the terms of the agreement rule.
But what if a joint copyright owners gets into a bad licensing deal? Essentially, there’s nothing you can do.
Determining the split before there’s money to fight about is the reason writers, for example, have co-publishing agreements that spell out the agreed to splits. That’s why you should work with an attorney to draft a licensing contract allowing the work to be licensed in a way that’s fair for all owners while maximizing the potential licensing revenue.