“Germany’s leading credit bureau, SCHUFA, has immense power over people’s lives. A low SCHUFA score means landlords will refuse to rent you an apartment, banks will reject your credit card application and network providers will say ‘no’ to a new contract. But what if your SCHUFA score is low because there are mistakes in your credit history? Or if the score is calculated by a mathematical model that is biased? The scoring procedure of the private company SCHUFA is highly intransparent and not accessible to the public.” - https://openschufa.de/
"[SCHUFA] is a German private credit bureau supported by creditors. It has its headquarters in Wiesbaden, the capital of Hessen, Germany. (…) Schufa has 943 million records on 67.7 million natural persons, and 6 million companies. Schufa processes more than 165 million credit checks each year. Of those, 2.5 million are self-checks by citizens.
(…) At the beginning of the 20th century, the Berlin city electric company (BEWAG) offered household appliances for sale on installment plans. At the time, the financing was compared with electric bills and only regularly paying customers would be supplied with appliances. This started a system for assessing payment behavior." - https://en.wikipedia.org/wiki/Schufa