This paper analyzes the implications of different interpretations of additionality for the market mechanisms under Article 6 and reflects on options how to anchor further additionality provisions in the negotiation text. The authors find that several quality criteria of mitigation outcomes are often discussed under the term additionality, but they need to be differentiated from one another. In the context of Article 6.2, additionality can be anchored through stringent international oversight, e.g. through the review of additionality by the A6TER. Particpating Parties can ensure additionality by applying stringent additionality test and controlling the quality of acquired ITMOs. In the context of Article 6.4, reliable additionality tests under the CDM can continue, with the addition of new tests for sectoral activities. Furthermore, options for additionality can be secured in the governance and responsibilities of the Article 6.4 Supervisory Body.