mark-up or mark-down
- 38(a) (when a firm receives a customer order and takes a principal position in the relevant investment in order to fulfil that customer order (that is, when the firm takes a principal position in the relevant investment which it would not otherwise take, except to fulfil that customer order)) the difference, if any, between:
- (i) the price at which the firm takes a principal position in the relevant investment in order to fulfil that customer order; and
- (ii) the price at which the firm executes the transaction with its customer;
- (b) (when a firm executes a customer order against its own book and owes a duty of best execution) the difference between: