This paper aims at providing a comprehensive overview of existing literature on the topic of comparability adjustments. Based on existing literature the most commonly used adjustments can be categorized in two broad categories: "accounting and financial risks adjustments" and "strategic/market adjustments". With the exception of working capital adjustments, the lack of guidance and recognized standardized application will quite possibly lead to continued discrepancies in their use. Taxpayers continue to struggle with the immense amount of documentation as well as justification requirements when it comes to adjustments, as there is no clear path to follow and very few practical application examples, which would unify the application of adjustments. As seen, even though the topic of comparability adjustments has been around since before the first version of the OECD TP Guidelines, the topic is yet to be fully explored in both official guidance as well as literature, research and especially practical tools. / Series: WU International Taxation Research Paper Series