Every rate, rule, and treaty reference on this site is checked against the sources below before it is published. These are the anchors: official government and treaty portals first, then the Big Four and second-tier firm reference guides used as secondary, citable checkpoints.
Government and treaty-body portals. These are authoritative - not summaries of the law, but the law and treaty text itself.
Full text of every US income tax treaty and protocol, plus Technical Explanations where available.
Summary tables of withholding rates by treaty article and income type, cross-referenced to Publication 901.
The UK's full treaty network, related taxation documents, and multilateral agreements.
Free, practitioner-authored reference guides covering most of the world's tax systems. Used as secondary sources with a last-verified date noted on each country page.
Corporate and individual tax systems in 150+ territories, written by local PwC specialists and updated through the year.
Corporate income tax, treaty withholding rates, CFC and anti-avoidance rules across roughly 150 jurisdictions.
Indirect tax systems - scope, rates, registration thresholds, and digital economy rules - across 150+ jurisdictions.
Hub for EY's full guide set, including personal tax, transfer pricing, and estate and inheritance tax guides.
Country tax highlights for 130+ jurisdictions plus a rates database covering corporate, withholding, and VAT/GST rates.
Entry point to KPMG's global tax practice pages and member-firm Tax Rates Online tools for corporate, indirect, and individual rates.
Additional practitioner guides used to cross-check specific topics, especially transfer pricing.
Country-by-country transfer pricing and Country-by-Country Reporting rules.
This list will grow as we verify additional second-tier and boutique international guides. If a firm publishes a free, citable global or regional tax guide we should be tracking, we welcome the suggestion via cpavalidated.com.
Every figure on Global Tax Guide is checked against at least one source above (or a national tax authority) before publication. Where our researchers could not independently verify a figure, the page says so explicitly - "not independently verified" - rather than presenting an estimate as fact. Nothing on this site is generated by extrapolation or pattern-matching from other countries' rates.