This white paper is published ahead of the second session of the Intergovernmental Negotiating Committee on Plastic Pollution (INC-2 in Paris, France, 29 May to 2 June 2023) with the aim to:

• Clarify the metrics that companies should use for plastic pollution accounting purposes, with a focus on the measurement of plastic leakage and circularity.
• Embed these metrics into a comprehensive corporate accountability system for plastic pollution that could help companies comply with the future International Legally Binding Instrument (ILBI) to end plastic pollution currently being negotiated by UN member states.

In this paper, we propose an accountability system consisting of four phases that frame the journey for companies to end plastic pollution and transition to a circular economy for plastics:

1. Set an ambition for the transition to compliance with the ILBI/science-based targets.
2. Translate the target into a plastic pollution action plan for implementation at the company level.
3. Derive accurate plastic pollution reduction accounting metrics (in line with agreed treaty goals) over time through an accounting mechanism for plastic pollution.
4. Disclose the metrics externally through a global baseline reporting framework for accountability (reporting and disclosure).