This approach paper examines the role of additionality for environmental integrity under Article 6.2 approaches. It analyzes the relevance of additionality determination methods from market mechanisms including Joint Implementation (JI), Clean Development Mechanism (CDM), and voluntary offset mechanisms, wherein additionality has been judged as a yes/no dichotomy, albeit with inherent uncertainty. It also reviews other performance-based market mechanisms such as emission trading systems, wherein no additionality demonstration was needed. A6.2 has more similarities with JI and International Emission Trading (IET), including the capping of emissions of all participants and performing corresponding adjustments (CA). It is noted that A6.2 differs from former project-based mechanisms, where the additionality demonstration has been linked to the absence of the project activity and relied on business-as-usual (BAU) scenario for baseline. The A6.2 guidance state that the impact of mitigation activities should be evaluated compared to a country's commitment and to future-looking performance of a below-BAU scenario. In the A6.2 context, the host country must assess and decide how much and which MO it wishes to sell, or not, to ensure it achieves its own NDC commitments, without overselling or underachieving by not engaging sufficiently in international markets. Additionality may become a risk management tool, rather than a yes/no decision tool, to determine the quantity of MO from an activity that may be authorized by the host country for international transfer. This approach paper provides scenarios of when and how activity-based additionality could be evaluated to mitigate risks to the host and buyer.