Tax Inspectors Without Borders (TIWB) helped developing countries collect an additional USD 2.72 billion in tax revenue by the end of 2025, while supporting USD 7.67 billion in tax assessments across 71 countries.
Tax Inspectors Without Borders (TIWB), a joint initiative of the Organisation for Economic Co-operation and Development (OECD) and the United Nations Development Programme (UNDP), helped developing countries collect an additional USD 2.72 billion in tax revenue by the end of 2025, according to its annual report published on 2 July 2026.
TIWB supported 71 developing countries through 165 programmes, with 51 programmes ongoing and 114 completed at the end of 2025. The initiative also contributed to USD 7.67 billion in tax assessments and the disallowance of USD 2.53 billion in carry-forward losses. It generated USD 125 in tax revenue for every dollar invested.
Africa recorded the largest gains, with USD 2.20 billion in collected revenue and USD 5.45 billion in tax assessments. Asia and the Pacific recorded USD 318.46 million in collected tax and USD 1.00 billion in assessments, while Latin America and the Caribbean recorded USD 122.20 million and USD 879.97 million respectively.
TIWB has expanded beyond transfer pricing and international tax audits to areas including Criminal Tax Investigation, Automatic Exchange of Financial Account Information, Country-by-Country Reporting, Digitalisation of Tax Administration, Implementation of the Global Minimum Tax and Auditing Value Added Tax (VAT) on Digital Trade. Its first pilot programme on the Global Minimum Tax was completed in North Macedonia in December 2025.
The report also highlights the launch of TIWB 2.0 in 2025, which introduced more flexible delivery models and plans for a TIWB Graduates Platform to strengthen South-South and triangular co-operation. For 2026, the initiative plans to support 51 ongoing programmes, start 12 new TIWB-audit and four new TIWB-CI programmes, launch at least three new South-South programmes and introduce mentoring initiatives to increase the participation of female tax experts.
