This report analyses the approaches of the previous five B20 presidencies to addressing anti-corruption Collective Action. It captures lessons learned and provides recommendations for future B20/G20 cycles. It is primarily intended for upcoming B20/G20 presidencies, B20 Integrity & Compliance Task Force members and organisations engaging with the B20/G20.

About this report

You may share or republish this report under a Creative Commons CC BY-NC-ND 4.0 licence.

Suggested citation: Scarlet Wannenwetsch. 2025. 'Anti-corruption Collective Action in the G20/B20 process: Charting progress 2020–2024.' Basel Institute on Governance.

The report was funded by the Siemens Integrity Initiative, which supports organisations in the fight against corruption and fraud through Collective Action, education and training. The views and opinions expressed in this report are those of the author and do not reflect the position of Siemens or the Siemens Integrity Initiative.