Their central bank is only sanctioned in about two dozen countries. It can conduct dollar transactions in India, for example. I assume the sanctions also cover

Their central bank is only sanctioned in about two dozen countries. It can conduct dollar transactions in India, for example. I assume the sanctions also cover Indian subsidiaries, so the Russians won't be able to trade against e.g. Goldman Sachs's Indian subsidiary. But there are plenty of banks that aren't owned by motherships in the two dozen sanctioning countries.