First, while it's true that the rights I refer to are generally valued based on the strength of the royalty streams, this does not mean that buyers and sellers value these rights in a strictly formulaic manner. As with any asset, there are a variety of factors that might result in buyers paying a premium. An investor with the ability to purchase rights associated with an Elvis Presley song, for instance, would probably pay substantially more for each dollar in royalties than they would for rights associated with a song by a less famous artist.

Second, and most importantly, not all royalties are tied to CD and digital music sales. These are mechanical royalties. There are also performance and synchronization royalties, which can be significant. It's is entirely possible, for instance, for a song that generates little in the way of mechanical royalties to generate eye-popping performance or synchronization royalties.