For suitable definitions of communism, a stock market is a good way to get the means of production into the hands of the workers: they can buy stocks and share ownership of the company they work for.
I don't claim to be an expert in politology, but what I remember from school seems to indicate that the common ownership of the means of production is the core idea of communism. I don't understand how a stock market is antithetical to that. As I see it, common ownership of the means of production can be achieved both with and without a stock market. Could you maybe elaborate your standpoint?
A stock market allows people to acquire ownership in companies, but it will be highly unequal: some of them will have more, some will have less, some will have none. That unequal ownership will generate correspondingly unequal rewards.
No communist system can allow that. Instead, the companies are uniformly state-owned and the rewards added to the state coffers where they will be pillaged and shared by the politically connected.
