Glossary
Royalty Decay
Royalty decay is the rate at which royalty income from a song, recording, book, patent or other intellectual property declines over time after its initial release or peak. Underwriters express it as an annual percentage decline and use decay curves to project future royalties when valuing catalogs or sizing advances and royalty-backed loans.
Formula
Example
A catalog earns $1,000,000 of royalties this year. At a 10% annual decay rate, projected royalties are $900,000 in year 1, $810,000 in year 2 and $729,000 in year 3, totaling $2,439,000. At a 5% decay rate, the same three years total $950,000 + $902,500 + $857,375 = $2,709,875, which is $270,875 more. Small differences in decay assumptions compound into large valuation gaps.
How it is used in underwriting
Decay is often the most important assumption in royalty and catalog underwriting. New releases typically decay steeply in their first few years, then flatten as the work settles into steady long-term earnings, so recent works and older works need different curves. Underwriters estimate decay from the catalog's own history, comparable catalogs and the mix of income sources, such as streaming, performance, synchronization and physical sales. They then project royalties, apply a discount rate or multiple, and test recoupment of any advance or repayment of a loan under base and downside decay scenarios.
Applying a single decay rate to an entire catalog is a common oversimplification. A catalog dominated by a few recent hits may decay far faster than one with older, established works. Income sources also behave differently: synchronization income is lumpy, while streaming income from established works can be relatively stable or even grow. Underwriters should separate the catalog by age and income type, check for one-time spikes such as a viral moment or a large sync placement, and normalize them. Royalty decay is distinct from changes in royalty rates set by contracts or regulators, which should be modeled separately.
Frequently asked questions
How do you calculate royalty decay?
Compare royalty income across periods for the same works, excluding new releases and one-time items, and compute the annual percentage decline. Underwriters often calculate decay separately by release age and income source, then combine them into a curve. Year-over-year changes are averaged or fitted to a model to project future royalties.
Why do newer songs decay faster than older ones?
New releases usually earn heavily during their initial promotional period and then decline as listener attention moves on. Works that remain popular years later have shown durable demand, so their earnings tend to be more stable. This is why catalogs of established works often command higher valuation multiples.
How does royalty decay affect catalog valuation?
Faster decay means lower future earnings and lower value. Because buyers and lenders project royalties many years forward, small changes in the decay assumption compound into large differences in projected income and present value. Underwriters typically show valuation and loan coverage across several decay scenarios.
Related terms
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