Turnover exclusion conditioned on prior payment of multi year turnover-based fees before excluding subsidiary sub-broker activity. The amendment provides that when a stock exchange's subsidiary acts as a stock broker for another exchange, the subsidiary may exclude turnover arising from a parent stock broker's trading through it as a sub-broker only if the parent stock broker has paid turnover-based fees covering a multi-year period plus the fee for a corresponding multi-year block on the stock exchange that formed the subsidiary.