The Spanish IAE activity code: what it is and how it is chosen

The short answer

A Spanish IAE heading is the code the tariff uses to classify your activity. It decides what the tax would cost and, above all, how the rest of the tax system treats you².

What a heading actually is

The tariff of the Spanish business activity tax is an annex to Legislative Decree 1175/1990 and orders everything a person can do for a living into a four-level hierarchy: division, group, sub-group and heading². Base two of article 85.1 of the consolidated Local Government Finance Act explains the criterion behind that order: headings «shall be ordered, as far as possible, in accordance with the National Classification of Economic Activities»¹. That is why the number is not arbitrary, and why it resembles the CNAE code without matching it.

There are three sections. The first covers business activities, which article 78.2 defines as independent livestock farming, mining, industry, commerce and services, running from division 0 to 9¹. The second covers professional activities, with the same ten-division structure. The third, far shorter, covers artistic activities in five groups.

The border between the first two is drawn not by the work done but by who does it. Rule 3 of the Instruction says professional activities are «those classified in Section 2 of the Tariffs, provided they are carried on by natural persons», and that where a legal person carries on one of them «it shall register and be taxed for the corresponding or analogous activity in Section 1»².

The same work, two headings and twice the quota

That transfer is not a formality. A lawyer who is an individual sits in group 731, whose quota the tariff sets at 44,402 pesetas, with the text printing its equivalent alongside: 266.86 euros. The same services supplied by a company go to group 841, «Legal services», with a quota of 88,803 pesetas, that is 533.72 euros².

The two figures hold an exact relation, easiest to see once the 3.5% uplift they carry is removed⁴: 42,900 and 85,800 pesetas. Double, with no decimals. The difference between practising as an individual and practising through a company has been written into the tariff since 1990.

The professional section has no taxpayers left

There is a consequence here that is rarely spelled out, and it can be checked by reading three articles in a row.

Article 88.1(b) grants, «in every case», a 50% relief on the quota to anyone starting any professional activity, for the five years following the end of the second tax period¹. It is mandatory throughout Spain and depends on no by-law.

But a professional activity is, under rule 3.3, one in section 2 carried on by an individual². And article 82.1(c) exempts every individual from the tax¹. Read together, the three provisions leave that relief with no possible beneficiary in common-regime territory: its only addressees are exempt from the tax it would reduce.

This is not a claim about what has ever happened: it is the chain of three readings, and anyone can redo it. What it does mean in practice is that section 2 of the tariff remains very useful, because it classifies and that classification decides withholding, but it has stopped raising money.

What your quota lets you do

Rule 4 opens with the strict statement: «payment of the quota corresponding to an activity entitles the taxpayer, exclusively, to carry on that activity». It then opens it up with a list of powers by family, worth knowing before registering a second heading²:

All of them also allow warehouses or depots closed to the public, whose floor area does count towards the tax element of the same name. And the rule closes with a warning that saves trouble: appearing on the roll or paying the tax «does not legitimise the carrying on of an activity» where the rules in force demand other requirements².

One quota per activity and another per premises

Rule 10.3 says it in both directions and in the same sentence: if the same activity is carried on in several premises, as many municipal quotas are paid as there are premises, and if several activities are carried on in the same premises, as many quotas are paid as there are activities, «even though they belong to the same person or entity»².

That multiplication is what makes the IAE a very uneven tax between companies of the same size. A chain with twenty shops pays twenty municipal quotas; a company billing the same from a single warehouse pays one.

What the tax actually measures

None of the elements that set the quota is profit. Rule 14 calls them tax elements and defines them one by one: installed power, reduced to kilowatts using the equivalence of 1 CV to 0.736 kW; the number of workers, which expressly excludes management, technical, commercial and delivery staff; the municipality's registered population; the capacity of entertainment venues, which unnumbered is estimated at one seat per 50 centimetres of row; and the floor area of the premises, measured by adding up every storey².

There is one element the rule mentions in order to say that it does not count: work shifts. «The quotas of the Tax entitle the taxpayer to carry on the activity, whatever the number of daily work shifts»². Running three shifts does not add a euro to the tax.

A worked example with real numbers

A lawyer registering as self-employed picks group 731 in section 2. The quota the tariff assigns to that group is 44,402 pesetas, 266.86 euros². She pays none of it: article 82.1(c) exempts her as an individual¹. What the heading does do is classify her activity as a professional one, which is why her invoices carry income-tax withholding.

Three years later she incorporates and moves the practice into a company. The company cannot register in group 731: rule 3.3 sends it to group 841 of section 1, «Legal services», with a quota of 88,803 pesetas, 533.72 euros². It pays nothing yet either, for two different reasons: article 82.1(b) exempts the first two tax periods, and after that article 82.1(c) keeps exempting it while turnover stays below one million euros¹. And its invoices stop carrying withholding, because the activity has become a business one.

If years later the company passes that million, it starts paying on the heading's 533.72 euros, multiplied by the article 86 weighting coefficient and by whatever its council and its provincial authority decide¹. That sum, with its two local multipliers, is in the IAE calculator.

How it is declared, and by when

The tax's census returns are three and Royal Decree 243/1995 governs them. Registration is filed before one month has passed since the activity started, and is made separately for each activity³. A variation, within one month of the circumstance that triggers it³. And deregistration, within one month of ceasing; if the taxpayer dies, their successors file it, counting the month from the death³.

There are two exceptions to that one-month rule and both fall in December: anyone who stops meeting an exemption's conditions files the registration «during the month of December immediately before» the year in which they become liable, and anyone who becomes exempt files the deregistration in that same month³.

Those three returns do not go on form 036 or 037, which is where the heading itself is stated: they go on form 840, and only anyone who is not exempt files them. If the municipality has delegated census administration, it is not even that form.

What this article does not settle

The concrete choice of heading for a mixed or novel activity, which depends on its real content and sometimes on a formal ruling; the particular notes attached to each heading, which can raise or lower the quota and which article 5.4 of Royal Decree 243/1995 requires to be expressly cited in the return³; and the rules of Navarre and the Basque historical territories, which have their own regime under their agreements.