Occasionally, a businessman may come across a good business opportunity that he is unable to take up either through lack of means or knowledge of the market.
Very often, to remedy this situation he decides to approach other complementary companies. One clear example of this type of company co-operation is an ‘export consortium’, through which a group of businessmen decide to join together to enter the outside market.
In effect, constituting a new entity that acts under its own name but is run by the members thereby sharing the costs incurred.
Another example of company co-operation is the case of manufacturers of different products joining together to form a company to access particular clients.
In order to create these associations of companies the appropriate legal format must be adhered to bearing in mind the type of association that is required and even the proposed period of time that the co-operation will be maintained.
In certain cases, it is not always appropriate to form a trading company, public or limited, due to their inflexibility and concept of permanency.
Therefore, under these circumstances, it is more convenient to form an Agrupación de Interés Económico - Association of Economic Interest - which is defined as follows:
Agrupaciones de Interés Económico (AIE) are legal trading companies formed by individuals or legal entities and are created to facilitate the development and improve the results of the members' activities.
AIEs do not gain profit in themselves, as the object is to act as an economic support to the businesses carried out by its members.
Members of an AIE are individually and jointly responsible for any debts incurred by the association.
The name of the association, which cannot be the same as any other existing association or company, must include the term Agrupación de Interés Económico or the initials AIE.
The AIE must be registered with the Company Registry, and the names of the members need to appear on the association's deeds together with the social capital, if it exists, the portion corresponding to each member, its name, purpose, company address, the administrator and any other agreements established.

Tax
AIEs pay tax on visible earnings and the tax situation differs to that of other companies.
AIEs do not pay company tax on the taxable rate attributed to its members  resident in Spanish territory.
Positive and negative taxable rates are applicable.
Therefore, the positive and negative taxable bases obtained by an AIE are attributed to the members, who in turn must include them in their corresponding company tax returns.
The tax responsibility of each member is in proportion to the company statutes of the Association for the tax period in which the AIE formulates its annual accounts.
Members of the AIE carry the association's accounts separate from their other businesses.
Procedures relating to the constitution of an AIE are exempt from transfer tax - Impuesto sobre Transmisiones Patrimoniales y Actos Jurídicos Documentados.
The same applies to the initial contracts, other legal documents needed for the constitution, members' monetary contributions, reduction in capital, liquidation of the association and also procedures taken to convert to another type of entity.
With regard to Value Added Tax, there are no special circumstances as an AIE receives goods and trades in the same manner as any other company.