Wikipedia - USSR
https://en.wikipedia.org/wiki/Eurasian_Economic_Union
"When the USSR began to fall in 1991, the presidents of Belarus, Kazakhstan and Russia of the founding republics signed the Belavezha Accords on 8 December 1991, declaring that the Soviet Union would cease to exist and proclaimed the Commonwealth of Independent States in its place."
https://en.wikipedia.org/w/index.php?title=Eurasian_Economic_Union&oldid=1215336828
https://en.wikipedia.org/wiki/Belovezha_Accords
Effective:
- Belarus Ukraine 10 December 1991
- Russia 12 December 1991
- Kazakhstan 23 December 1991
- Tajikistan 25 December 1991
- Armenia Turkmenistan 26 December 1991
- Uzbekistan 4 January 1992
- Kyrgyzstan 6 March 1992
- Azerbaijan 24 September 1993
- Georgia 3 December 1993
- Moldova 8 April 1994