An asesor or asesor fiscal is a consultant, an accountant, who deals with matters pertaining to taxes and the Hacienda, the Spanish Tax Office.
They are used by anyone, resident or non-resident, who declares income tax to the Hacienda, be it personal or for a business and who doesn’t want to fill out the necessary forms themselves. As with all Spanish paperwork, tax forms are complex and time-consuming to complete correctly, which is why the majority of sane people employ an asesor to take care of it for them.
The question is often asked, ‘what is the difference between a gestor and an asesor?’ While there are several areas in which the duties of a gestor and asesor, and even an abogado (lawyer), overlap, the basic difference is:
A gestor is an advisor or consultant acting as an intermediary with the authorities but who does no more than could be done by a member of the public themselves. It is their knowledge of the intricacies of the system and their ability to use that knowledge to ensure that forms etc are completed correctly and in a timely manner which makes them useful.
An asesor fiscal is a professional accountant used primarily for dealings with the Spanish Tax Office, the Hacienda.