The loss certificate is a document your bank issues only on request, and that request has a hard expiry date. Section 43a(3) sentence 5 of the German Income Tax Act devotes a single sentence to it: the irrevocable request “must reach the paying agent by December 15 of the current year”. Reaching means arriving, not posting. So anyone holding crypto ETNs or crypto ETPs in a securities account at a German bank and sitting on a loss there decides over the coming eight weeks whether that loss will ever reduce a tax payment.

One distinction matters right at the start: this text is about crypto securities in a securities account, not about coins on a trading platform or in your own wallet. Directly held coins fall under Section 23 of the…