Cuba is your best example, however, it is a socialist state and not communism.

China has three stock exchanges and is not communist:

• http://english.sse.com.cn/
• http://www.bse.cn/
• https://www.szse.cn/English/index.html

The USSR never got to the “people’s dictatorship”, ya know, because the dictators never completed that step. Despite being a very powerful country at their peak, the USSR only exists as a memory of a failed state.