Can't speak for every country, but in Sweden for example tax data to a certain level of detail (income by labor, income by capital) is publicly available for ea

Can't speak for every country, but in Sweden for example tax data to a certain level of detail (income by labor, income by capital) is publicly available for each citizen. Same for debts. And debts that go to the collection authority, which has a very dark name (kronofogden), are very public and somewhat worse than having to wear a scarlet letter. So credit institutes have enough of an idea of your finances to decide your rate.