This is the description found on their "About Us" in English [1]:
Stiftung Warentest is a foundation. It was established in 1964 by the German federal parliament with the aim of helping consumers by providing impartial and objective information based on the results of comparative investigations of goods and services.
We buy products – anonymously from retailers, and make covert use of services.
We carry out tests – in independent labs that use scientific methods and follow our specifications.
We give verdicts – ranging from „very good“ to „unsatisfactory“, based solely on objective results.
We publish our findings – totally free of adverts in our magazines „test“ and „Finanztest“, and online at www.test.de.
According to their report [2] they are mostly financed through the sale of their articles.
Stiftung Warentest is a foundation. It was established in 1964 by the German federal parliament with the aim of helping consumers by providing impartial and objective information based on the results of comparative investigations of goods and services.
According to their report [2] they are mostly financed through the sale of their articles.[1] https://www.test.de/unternehmen/about-us-5017053-0/
[2] https://www.test.de/unternehmen/zahlen-5017275-0/