The IMMB is an autonomous body responsible to Barcelona City Council. The Institute can exercise this autonomy in administrative matters and in relation to managing its own budget, within the framework of the general fiscal regulations approved by the City Council.

As regards regulation, on 1 January 2009 a new municipal market byelaw came into force which updated the 1968 byelaw. The drafting of the new byelaw and its approval in December 2008 marked the culmination of a process of modifying market regulations that had begun in 1978 and intensified following the setting up of the IMMB.

The new byelaw was passed with the aim of updating the existing legislation, introducing new points and bringing it into line with the real situation.