Executive summaryThe Czech bill amending the Act on International Cooperation in Tax Administration implementing the European Union (EU) Directive on the mandatory disclosure and exchange of cross-border tax arrangements (referred to as DAC6 or the Directive) was published, on 14 August 2020, in the Czech Collection of Laws.The final Czech Mandatory Disclosure Rules (MDR) legislation is effective from 29 August 2020.Also, on 7 September 2020 the Czech Government approved a six-month deferral to the initial MDR reporting (deferral regulation) which was officially published on 10 September 2020. The deferral regulation generally follows the Council amendment to the EU Directive 2011/16 allowing Member States an option to defer...