Retention
Involuntary churn
Customers lost because a payment failed rather than because they chose to leave. Usually the cheapest churn to recover.
Involuntary churn is a customer leaving without deciding to. A card expired, was reissued after a fraud alert, hit a limit, or a bank declined a renewal for a reason nobody at either company ever sees.
It is commonly 20% to 40% of all churn in a card-billed subscription business, and it is the only churn that is fixed with mechanism rather than persuasion: smart retries timed to the decline reason, a dunning sequence that reaches the person who can update the card, account updater services, and a grace period that does not switch off the product on day one.
If you do not separate it from voluntary churn, you will read a payments problem as a product problem and go and rebuild a feature that was never the reason.