The Convention on Mutual Administrative Assistance in Tax Matters is a convention to facilitate the entering into bilateral tax information exchange agreements between state parties. The Convention was developed by the OECD and the Council of Europe and was open for signature to members of both organizations on 25 January 1988, and entered into force in 1995. The Convention on Mutual Administrative Assistance in Tax Matters is a convention to facilitate the entering into bilateral tax information exchange agreements between state parties. The Convention was developed by the OECD and the Council of Europe and was open for signature to members of both organizations on 25 January 1988, and entered into force in 1995.