I wonder who will be quoting Transfermarkt after reading this article?
Top football clubs relying on transfer valuations made by volunteers
Valuations by the football data website Transfermarkt, which can often influence transfer negotiations and have appeared on several clubs’ annual financial reports, are determined mainly by volunteers, according to an investigation.
https://www.theguardian.com/football/2020/dec/19/top-football-clubs-relying-on-transfer-valuations-made-by-volunteers?CMP=Share_iOSApp_Other