*Loan,banking and credit>>>credit score

Does selling a collection acount to another collection account hurt your credit score?

If you talking about accounts being sold and resold and resold
no.Once it is leaves the original Creditor and goes to a collection agency it doesn't matter how many times it is sold but you want to keep an eye on who really owns the debt the only way to confirm that is through debt Validation.The good news is the debt gets harder to validate when it gets sold many times paper work gets lost.

Of course, they wrote the account off as a loss They can only get a certain percent back on a dollar.
Crazy Cat Lady is correct. If a collection agency is not getting any progress with an account a lot of times they sell them to another agency. Sometimes agencies have more tools and resources to "track you down" or find out important information like your current employer, new address or phone numbers. But by agencies buying the accounts it does not hurt you credit score.