(23)However, in order to avoid any potential misuse of exemptions, market makers in financial instruments, other than market makers in commodity derivatives, emission allowances or derivatives thereof provided that their market making activity is ancillary to their main business considered on a group basis and provided that they do not apply a high-frequency algorithmic trading technique, should be covered by the scope of this Directive and should not benefit from any exemption. Persons dealing on own account when executing client orders or applying a high-frequency algorithmic trading technique should also be covered by the scope of this Directive and should not benefit from any exemption.