Austria and Luxembourg were among the latest tranche of nine countries to sign up to the OECD's Multilateral Convention on Mutual Administrative Assistance in Tax Matters to fight tax evasion and improve global tax compliance.
The other seven were Singapore, Estonia, Latvia, Belize, Nigeria, Saudi Arabia and the Slovak Republic.
It further cements moves made in April when Luxembourg - which holds assets worth around 22 times the country's annual economic output of €44bn (£37bn) - announced it would start exchanging financial information with its EU partners as part of the European-wide bid to help fight tax evasion. The Duchy's move heaped pressure on Austria, then the only remaining EU country not to have signed up for tax information exchange.
In addition to the nine new signatories, Chile, El Salvador and Burkina Faso all signed a letter of intention to sign the Convention and another six countries have ratified the convention.
The convention was developed jointly by the OECD and the Council of Europe in 1988 and amended by Protocol in 2010.
At the signing ceremony in Paris on 29 May 2013, OECD secretary-general Angel Gurrua said: 'This convention is the most comprehensive multilateral instrument available for all forms of tax co-operation, and for tackling tax evasion and avoidance, a top priority for all countries. It allows, among other things, automatic exchange of information, simultaneous tax examinations and assistance in the collection of tax debts. It is therefore no coincidence that it has the strong support of the G20, and that more and more countries are joining the convention.'
The convention provides a legal basis for the standardized multilateral automatic exchange model being developed at the OECD with G20 partners, and complements initiatives such as the peer review process of the Global Forum on Transparency and Exchange of Information for Tax Purposes.
As a sign of their continued support for the convention, G20 finance ministers and Central Bank governors said at their last meeting that they 'strongly encourage all jurisdictions to sign or express interest in signing the Multilateral Convention on Mutual Administrative Assistance in Tax Matters and call on the OECD to report on progress'.
In the past two years, more than 60 countries have signed the convention or stated their intention to do so, marking an important milestone on the road to making the international system fairer for all taxpayers.
More details are available from OECD