This report takes stock of TIWB’s achievements so far and charts the path ahead as it enters its second decade. Since its launch, 165 programmes across 71 jurisdictions have generated USD 2.72 billion in additional tax revenue, with a further USD 7.67 billion assessed. It highlights key milestones, including the launch of TIWB 2.0, its recognition under the Sevilla Platform for Action, and the introduction of the TIWB Graduates Platform. Looking forward, the report explores how the initiative will continue to strengthen partnerships and support jurisdictions in tackling evolving tax challenges through practical, hands-on capacity building, tailored to the needs of host administrations.
Tax Inspectors Without Borders (TIWB) Annual Report 2026
USD 2.72 billion
Additional tax collected by host administrations, thanks to TIWB programmes, to date
USD 7.67 billion
Additional tax assessed by host administrations, thanks to TIWB programmes, to date
Tax Inspectors Without Borders (TIWB) connects global tax experts to strengthen local expertise and solve real tax challenges for developing country tax administrations
TIWB is a joint initiative of the Organisation for Economic Co-operation and Development (OECD) and the United Nations Development Programme (UNDP) supporting developing countries in building tax audit and investigation capacity.
Through its technical assistance programmes, TIWB complements the broader efforts of the international community to strengthen co-operation on tax matters and contribute to the domestic resource mobilisation efforts of developing countries. TIWB programmes in African jurisdictions are delivered jointly with the African Tax Administration Forum (ATAF) – TIWB's strategic partner on the continent.
Areas of technical assistance
TIWB's technical assistance is demand-driven and offered in various domains of international taxation to assist developing countries in enhancing the quality and consistency of international tax audits and/or investigations.
International tax audit
International tax audit programmes bring international audit experts to work directly with local tax officials on real audit cases and audit-related issues in transfer pricing and international taxation, bridging the gap between theory and practice. This assistance mainly provides support on audits of multinational enterprises.
Auditing value added tax (VAT) on digital trade
Auditing VAT on digital trade pilot programmes bring global tax experts to work directly with tax officials in host administrations to audit and enforce compliance with domestic rules for the collection of VAT on digital trade in accordance with internationally agreed VAT standards. This assistance can provide support on individual audit cases and assist in building capacity.
Digitalisation of tax administration
Pilot programmes for the digitalisation of tax administration offer confidential management-level advice on strategic topics related to digitalisation. The advice may relate to assessing the tax administration’s digital maturity, developing, or revising the administration’s digital strategy, or other assistance in a particular digitalisation area where high-level strategic advice is required.
Advance Pricing Agreements (APAs)
Support for tax administrations in negotiating APAs, agreements that define transfer pricing methods in advance of related-party transactions. Experts provide hands-on assistance throughout the full APA lifecycle, including risk assessment, functional analysis, benchmarking, paper drafting, and negotiations. By transferring practical expertise in both process and economic analysis, TIWB helps build sustainable APA capacity, increase tax certainty for taxpayers, and reduce transfer pricing disputes.
Criminal tax investigations
Criminal tax investigation programmes partner experienced financial crime investigators with a host administration to provide real-time assistance on complex tax crime cases and related capacity building.
Implementation of the Global Minimum Tax
Pilot programmes for the implementation of the Global Minimum Tax provide on-the-job support to countries in the practical implementation of global minimum tax rules. Experts deployed provide support on sensitive policy matters including assessing the potential impact of the global minimum tax i.e. determination of in-scope MNEs, effective tax rates, assessment of tax incentives etc the experts will also provide, recommendation on drafting guidance, law and regulations to implement the global minimum tax into domestic law.
Mutual Agreement Procedure (MAP)
Assistance for tax administrations in resolving cross-border tax disputes through MAP under bilateral tax treaties. Experts work on live cases, supporting all stages from case admission and analysis to negotiation and outcome documentation. Drawing on experience from Competent Authorities, local capacity is strengthened to handle disputes effectively, improving tax certainty, eliminating double taxation, and fostering stronger treaty partner relationships.
Implementation and effective use of Country-by-Country Reporting
Implementation and effective use of Country-by-Country Reporting (CbC reporting or CbCR) programmes provide on-the-job support to countries in the in identifying BEPS-related risks and assessing high-level transfer pricing through CbC data.
Effective use of automatic exchange of financial account information (AEOI / CRS)