I just realized that I should have declared ETFs I bought in 2015 and subsequently sold at a loss in 2016. They are non-German thesaurierend ETFs in a German bank so I thought my Freistellungsauftrag will cover the taxes I needed to pay. I've submitted my tax declarations already for those years, and received the tax refunds. However, those tax declarations did not include Anlage KAP (because I thought it's already fine with the Freistellungsauftrag). I would like to correct this mistake. Does anyone know how to submit the Anlage KAP even after I already received my tax refund? Any help/info would really be helpful.