The majority of the capital and voting rights in an audit company must be held by auditors qualified in Spain or other EU Member States. Spanish or EU nationality is required to become a licensed auditor, with an exception made regarding certain types of auditing practice (for entities not based in Spain). Third-country auditors are authorised subject to reciprocity and domicile or permanent establishment in Spain or a representative with domicile in Spain.
"Article 9. Authorization and registration in the Official Register of Accounts Auditors.
1. To be registered in the Official Register of Account Auditors, the following will be required: [...]
b) Have Spanish nationality or that of one of the Member States of the European Union, without prejudice to the provisions of the regulations on the right of establishment.
[...]
Article 10. Auditors of accounts authorized in other Member States of the European Union and in third countries.
1. Accounts auditors authorized to carry out the activity of auditing accounts in other Member States of the European Union may register in the Official Register of Account Auditors, in the terms that are determined by regulation. [...]
2. The auditors authorized to carry out the activity of auditing accounts in third countries, under reciprocal conditions, who meet requirements equivalent to those required in letters a), b) and c), may register in the Official Register of Account Auditors. of article 9.2, as well as the obligation of continuous training referred to in article 8.7.
To obtain authorization from the Accounting and Auditing Institute, they must prove, at least, compliance with the requirements established in letters a) and c) of article 9.1, pass an aptitude test equivalent to that referred to in the previous section, in the terms that are determined by regulation, and have a domicile or permanent establishment in Spain or designate a representative with domicile in Spain.
3. Without prejudice to the provisions of the European Union regulations, the auditors authorized to carry out the activity of auditing accounts in third countries who issue audit reports on annual accounts or consolidated annual accounts of an entity incorporated outside the European Union and whose securities are admitted to trading on an official secondary market in Spain, except when the audited entity exclusively issues obligations, bonds or other negotiable debt securities that meet any of the following conditions:
a) That they have been admitted to trading on an official secondary market in Spain before December 31, 2010 and whose nominal value per unit is at least 50,000 euros on the date of issue.
b) That they have been admitted to trading on an official secondary market in Spain after December 31, 2010 and whose nominal value per unit is at least 100,000 euros on the date of issue.
This exception will not apply when the entity issues securities that are comparable to the shares of companies or that, if they are converted or if the rights they confer are exercised, give the right to acquire shares or securities comparable to shares.
The auditors referred to in this section must meet the following conditions:
1. Comply with the requirements equivalent to those set forth in articles 9.1, letters a) and c), and 9.2, letters a) and b).
2. Appoint a representative domiciled in Spain.
3. Make the audit reports referred to in this section in accordance with the international auditing standards adopted by the European Union and as stipulated in sections 1 and 2 of chapter III of title I or, in your case, in accordance with the standards and requirements declared equivalent by the European Union.
4. That they have published on their website the annual transparency report referred to in article 37, or a report that meets the equivalent information requirements.
The registration in the Official Register of Account Auditors of these account auditors does not entitle them to carry out the activity of auditing accounts in relation to entities domiciled in Spain.
Notwithstanding the provisions of the European Union regulations, the audit reports issued by these third-country auditors not registered in the Official Register of Account Auditors will not have legal effect in Spain.
Article 11. Audit companies.
1. Commercial companies that meet the following requirements may be registered in the Official Register of Account Auditors as account auditing companies:
a) That the natural persons who carry out the work and sign the audit reports on behalf of an audit firm are authorized to carry out the activity of auditing accounts in Spain.
b) That the majority of the voting rights correspond to account auditors or audit firms authorized to carry out the activity of auditing accounts in any Member State of the European Union.
c) That a majority of the members of the administrative body are partner auditors of accounts or audit companies authorized to carry out the activity of auditing accounts in any Member State of the European Union.
In the event that the administrative body has no more than two members, at least one of them must meet the conditions established in this section.
2. The provisions of article 9.5 shall apply to audit firms. Likewise, Law 2/2007, of March 15, on professional companies will be applicable to account auditing companies as long as it does not contravene this Law. [...]" (Law on Auditing of Accounts (22/2015, of July 20), in force from 21 July 2015 (subsequently amended), Articles 9, 10 and 11 [google translation])
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"Article 4. Composition.
1. They are professional partners:
a) Natural persons who meet the requirements for the exercise of the professional activity that constitutes the corporate purpose and who exercise it within it.
b) Professional societies duly registered in the respective Professional Associations that, constituted in accordance with the provisions of this Law, participate in another professional society.
2. As a minimum, the majority of the capital and voting rights, or the majority of the corporate assets and the number of partners in non-capitalist companies, must belong to professional partners.
3. Likewise, at least half plus one of the members of the administrative bodies, where appropriate, of the professional societies, must be professional partners. If the management body is unipersonal, or if there are CEOs, these functions must necessarily be performed by a professional partner. In any case, the decisions of the collegiate administrative bodies will require the favorable vote of the majority of professional partners, regardless of the number of concurrent members. [...]"(Law on professional companies (2/2007, of March 15), last amended on 23 December 2009, Article 4 [google translation])
Law on Auditing of Accounts (22/2015, of July 20), in force from 21 July 2015 (subsequently amended), Articles 9, 10 and 11 
Law on professional companies (2/2007, of March 15), last amended on 23 December 2009, Article 4
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