Double Taxation Avoidance Agreement is in place between Russia and the United States – it means, what taxes on income, earned on American exchanges, a resident of the Russian Federation will pay only in his own country (13%).
If you open account on American exchanges through Russian broker, then broker становиться вашим налоговым агентом – he himself is obliged to calculate and pay your taxes on income, ежегодно забирая их с вашего Account, as well as when withdrawing funds from Account.
If you open check American broker directly, then you yourself must complete the annual tax declaration and pay taxes to the Russian budget.