If you carry out several activities you must determine whether they are so-called "distinct sectors" because, if so, you must apply the deduction scheme separately.
To determine whether economic activities are different:
You need to know the assigned group (the first 3 digits) in the National Classification of Economic Activities (CNAE-2009).
If they belong to different groups, they are considered to be different activities.An activity ancillary to another activity is not considered to be different if, in the preceding year, its volume of operations did not exceed 15 per cent of that of the latter and, in addition, contributes to its realisation.Ancillary activities follow the same system as the activities on which they depend.If the ancillary activity was not carried out in the previous year, a reasonable forecast of these operations should be made and regularised, where appropriate, once the volume is known.
Determining the deduction system.The deduction systems are different if, between the deduction rates (pro rata) applicable to the main activity (activity with the highest turnover in the previous year) and those applicable to activities other than the main activity, there is a difference of more than 50 percentage points.
The main activity, with the ancillary activities to it and the other different economic activities whose deduction rates do not differ by more than 50 percentage points from that of the main activity, shall constitute a single distinct sector.
The activities other than the main activity whose deduction rates differ by more than 50 percentage points from that of the main activity shall constitute another sector distinct from the main one.
In addition, the following always constitute distinct sectors:
The activities included in the simplified special schemes, agriculture, stockbreeding and fishing, of the transactions with investment gold or the equivalence surcharge.
The financial leasing operations ( DA 3rd of Law 10/2014).
The credit or loan assignment transactions (except for factoring).