On January 31st, 2019, the Supreme Court of Denmark (Højesteret) gave its decision in the case of Skatteministeriet v. Microsoft Danmark ApS (Case 75/2018). This case concerned two questions: firstly, whether the transfer pricing documentations submitted by Microsoft Danmark ApS (hereinafter: Microsoft Denmark) for the fiscal years 2004 to 2007 were compliant with the Danish transfer pricing documentation requirements; secondly, whether the marketing activities performed by Microsoft Denmark on behalf of Microsoft Ireland Operations Limited (hereinafter: MIOL) during the income years 2004 to 2007 provided a compensable benefit to another non-Danish Microsoft group company. The case, and subsequently this article, highlights the important connection between procedural and substantive transfer pricing rules, whereby non-compliance with the Danish transfer pricing documentation rules could result in the Danish tax authorities making a discretionary assessment on the taxable income, the result being a shift in the burden of proof from the Danish tax authorities to the taxpayer.