Stamp duty reserve tax

Stamp duty reserve tax is an HMRC tax levied on transactions in UK equities. If dealings between the client and the executing broker were to result in a legally binding agreement to transfer UK equities to the client or another person (the SDRT legislation is explicitly drafted so that the charge applies even if the agreement is to transfer UK securities to someone other than client) stamp duty reserve tax (SDRT) could apply.

Executing broker will generally be exempt from SDRT when it buys UK equities for its own account in the process of handling client orders (i.e. where it is acting as a principal and not an agent), but SDRT will apply on the corresponding sale between the executing broker and the client, so the revenue will get its pound of flesh (and actually more, because tax is payable on the gross price including commission).