Sociedad Limitada Unipersonal (SLU) in Spain: What It Is, Advantages, and How to Set One Up

The Sociedad Limitada Unipersonal (SLU), Spain’s single-member limited liability company, is the natural legal form for two very different profiles that share one need: the entrepreneur who wants to operate solo with their personal assets protected, and the foreign group setting up a wholly owned Spanish subsidiary. In both cases, the SLU offers the same thing: a full Sociedad Limitada, with its own legal personality and limited liability, whose capital belongs to a single shareholder, whether an individual or a legal entity.

That said, single-member status isn’t just an S.L. with one fewer partner. The Capital Companies Act devotes a special regime to it (articles 12 through 17) with additional transparency obligations and, above all, two traps that can blow up the sole shareholder’s limited liability: failing to register supervening single-member status, and failing to document the contracts between the shareholder and their own company. This guide explains exactly what the SLU is, when it pays off versus self-employed status, what limited liability actually protects, what specific obligations it carries, and how to set one up step by step in 2026, including the case of the foreign shareholder.

What Is the Sociedad Limitada Unipersonal?

The SLU is a limited liability company whose capital belongs entirely to a single shareholder. The law recognizes two ways of getting there:

• Original single-member status: the company is set up from the outset with a single shareholder, whether an individual (the solo entrepreneur) or a legal entity (the foreign parent creating its wholly owned Spanish subsidiary).
• Supervening single-member status: an S.L. with several partners ends up with just one because all the quota shares wind up in the same hands (purchase of shares, inheritance, departure of partners).

In everything essential, the SLU works like any S.L.: minimum capital of 1 euro following the Crea y Crece Act (with the special conditions below 3,000 € we’ll cover), quota shares, a freely chosen governing body (a sole director is the norm), and taxation under Corporate Income Tax. The difference lies in the disclosure regime: as long as the company is single-member, it must state that condition by adding the tag “SLU” or “Sociedad Limitada Unipersonal” across all its documentation, correspondence, invoices, and notices, and the identity of the sole shareholder (and every change of sole shareholder) must be recorded at the Commercial Registry.

One convenient practical quirk: in the SLU there are no general meetings with notice requirements and majorities. The sole shareholder exercises the meeting’s powers alone, and their decisions are documented in minutes signed by the shareholder or their representative. Less red tape, more agility, decisions made the same day.

Advantages of the SLU Over Self-Employed Status

This is the comparison every solo entrepreneur in Spain runs, and it’s worth laying out honestly, because the SLU doesn’t always win. Its real advantages:

• Limited liability: the self-employed worker answers for the business’s debts with all their present and future assets (article 1911 of the Civil Code): home, savings, car. In the SLU, the general rule is that the debts belong to the company and the shareholder risks only what they contributed.
• Flat taxation versus progressive personal income tax: the self-employed worker is taxed under personal income tax (IRPF) with marginal rates that top 45% in the higher brackets. The SLU is taxed under Corporate Income Tax at the general 25% rate, at 15% for the first two profitable years for newly formed entities, and with the new reduced rates for micro-enterprises: in 2026, companies with turnover below 1 million euros apply 19% to the first 50,000 € of the tax base and 21% to the rest.
• Optimizing how you pay yourself: the sole shareholder can combine a salary or director’s compensation (a deductible expense for the company) with dividend distributions, fine-tuning their personal tax bill, something impossible for the self-employed worker, who is taxed on the entire profit no matter what.
• Image and access to contracts: many companies, government bodies, and corporate clients require or prefer to contract with companies. The SLU professionalizes the brand compared to the self-employed worker’s personal tax ID.
• Scalability and sale: an SLU can bring in partners or investors through a simple transfer of quota shares, and the business can be sold as a company (with its tax ID, contracts, and seniority). A self-employed worker’s business, by contrast, is legally inseparable from the person.

The counterweights, because there are some: the SLU entails full commercial accounting, filing of annual accounts, higher advisory costs, and the shareholder-director paying contributions as a corporate self-employed worker (autónomo societario) under the RETA regime. On top of that, taking money out of the company has its own tax cost (salary or dividends), whereas the self-employed worker has direct access to their profit. The sector’s rule of thumb: with recurring profits below 40,000-50,000 € a year, self-employed status is usually more efficient; beyond that threshold, the scale tips toward the company. We develop the full comparison, with numbers, in our guide on self-employed status vs a Sociedad Limitada, and if you decide to stay self-employed, it’s worth having a firm handle on the tax obligations of the self-employed in Spain.

Real Limited Liability: What It Protects and What It Doesn’t

This is the most important section of the article, because the SLU’s limited liability is real but it’s not a magic shield, and it’s worth knowing its cracks before entrusting the family assets to it. What it does protect: the company’s ordinary commercial debts (suppliers, leases, services) are confined to the company’s assets. What it doesn’t protect, or protects only with conditions:

• Personal guarantees: banks, well aware of limited liability, routinely require the shareholder’s personal guarantee on loans and credit lines. Every guarantee you sign is a door opened straight to your personal assets.
• Director liability: if the sole shareholder is also the director (the typical case), they answer personally for damage caused by acts contrary to the law or the bylaws, or carried out without due diligence. And there’s a particularly dangerous scenario: if the company falls into a legal ground for dissolution (for instance, losses that drop net equity below half the capital) and the director neither dissolves it nor files for insolvency within 2 months, they become jointly and severally liable for the company debts that arise afterward (article 367 of the Capital Companies Act).
• Clawback of tax and Social Security debts: the Tax Agency and the Social Security Treasury can shift liability for tax and contribution debts onto the director in cases of violations, cessation of activity without an orderly wind-down, or obstruction of collection.
• The 6-month trap (article 14 of the Capital Companies Act), exclusive to single-member status: if single-member status is supervening and 6 months pass without registering it at the Commercial Registry, the sole shareholder becomes personally, unlimitedly, and jointly and severally liable for all company debts incurred during the single-member period. Once single-member status is registered, protection is restored for subsequent debts. This is probably the most expensive and least known mistake in the SLU regime.
• Undocumented shareholder-company contracts (article 16 of the Capital Companies Act): contracts between the sole shareholder and their company that aren’t transcribed into the register book and aren’t reflected in the annual notes can’t be asserted against the insolvency estate in the event of insolvency proceedings. In addition, for 2 years the sole shareholder answers to the company for any advantages they obtained to the company’s detriment through those contracts.
• Capital below 3,000 €: if you incorporated with the symbolic minimum of the Crea y Crece Act, in a wind-down with insufficient assets you’re jointly and severally liable for the difference between your capital and the 3,000 €.

The right way to read this: the SLU protects very well anyone who runs it with discipline (accounts filed, coherent capital, documented decisions, written contracts, a quick reaction to losses) and protects poorly anyone who treats it as an informal extension of their own wallet. Formal discipline isn’t bureaucracy: it’s the price of the shield.

Additional Accounting and Registry Obligations of the SLU

The SLU carries the same obligations as any S.L.: accounting kept to the General Accounting Plan, legalization of books, preparation and filing of annual accounts with the Commercial Registry, Corporate Income Tax, VAT, and withholdings. On top of that common package, single-member status adds four specific obligations:

• Disclosure of single-member status: the “SLU” tag must appear across all documentation, invoices, correspondence, order forms, and notices for as long as single-member status lasts.
• Registry recording of single-member status: the single-member incorporation, supervening single-member status, the loss of that status, and every change of sole shareholder are set out in a public deed and recorded at the Commercial Registry, with the identity of the sole shareholder.
• Minutes of the sole shareholder’s decisions: the decisions that in an S.L. would fall to the general meeting are recorded in minutes, signed by the shareholder or their representative, in the company’s minute book.
• Register book of contracts with the sole shareholder: every contract between the shareholder and the company (a lease of the shareholder’s premises to the company, loans from the shareholder to the company or vice versa, provision of services) must be in writing, transcribed into a legalized register book, and referenced expressly and individually in the annual notes, stating its nature and terms.

A tax note that goes hand in hand with that last obligation: transactions between the sole shareholder and their company are related-party transactions and must be valued at arm’s length. A token rent or an interest-free loan between the shareholder and their SLU is exactly the kind of item the Tax Agency scrutinizes closely in audits of single-member companies.

The Incorporation Process: Steps and Costs

Setting up an SLU follows the same circuit as any S.L., with the sole particularity that the deed will declare single-member status. The steps:

• Obtaining the NIE for the shareholder and director if they’re foreign (or an entity tax ID if the sole shareholder is a foreign company).
• Requesting the negative name-clearance certificate from the Central Commercial Registry, proposing up to three names in order of preference.
• Opening a bank account in the name of the company in formation and depositing the capital, with a bank certificate for the notary (for cash contributions).
• Drafting the bylaws: corporate purpose, registered office, capital and quota shares, and governing body, with particular attention to the director’s compensation if they’ll be paid for the role.
• Executing the public deed of incorporation before a notary, with an express declaration of single-member status and the identity of the sole shareholder.
• Registration at the Commercial Registry of the province where the registered office is located.
• Obtaining the definitive tax ID, tax registration with the Tax Agency (form 036) and, where applicable, registering the director under the RETA regime and the company as an employer with Social Security.

On costs, a standard incorporation with advice runs between 600 € and 1,500 € across notary, registry, and professional handling. If it’s filed online through the CIRCE system with standard-form bylaws, the notarial and registry fees drop to almost token amounts, the registry clearance happens within hours, and the company can be up and running in 24 to 72 hours. The full process, with every step explained, is in our guide on how to create a company in Spain, and if you’d rather hand it off entirely, our company incorporation in Spain service handles it from start to finish, including the immigration side when the shareholder isn’t Spanish.

Can a Foreigner Set Up an SLU in Spain?

Yes, without restrictions and without needing to reside in Spain. Any foreign individual or legal entity can be the sole shareholder of an SLU by first obtaining the NIE (or the entity tax ID for foreign parent companies), which can be processed through the Spanish consulate in the country of origin or through a representative holding a power of attorney, making it possible to incorporate the company entirely remotely. That said, it’s worth separating two planes that are constantly confused:

• Owning the SLU requires neither residence nor any kind of authorization: an investor living in their own country can be the sole shareholder of a Spanish company and receive dividends.
• Working in the company from Spain is another matter: if the non-EU foreign shareholder is going to reside in Spain and act as an executive director or work in their own company, they need a self-employed residence and work authorization, whose file assesses the business plan, the investment, and the financial means. That’s exactly what our self-employed work permit in Spain service covers.

EU, EEA, and Swiss citizens fall outside this second requirement: they can set up their SLU, reside, and work in it with the sole formality of the EU citizen registration certificate. For the full map of scenarios by nationality and situation, our guide on how to start a business in Spain as a foreigner runs through all the combinations.

When Does the SLU Make Sense Over an S.L. with Several Partners?

The right question isn’t so much SLU or S.L., because they’re the same entity, but whether it suits you to go into business alone or with others from a corporate standpoint. The SLU is the right choice when:

• You want total control of decisions without negotiating with anyone: no meetings, no majorities, no shareholders’ agreements, no deadlocks.
• The project is a wholly owned subsidiary of your foreign company, where the parent must be the sole shareholder by group design.
• The business depends essentially on your work and judgment, and collaborators fit better as employees than as partners.

A multi-member S.L. makes sense when the project needs capital or capabilities you don’t have (an investor partner, a technical partner), accepting the governance cost that comes with it: a shareholders’ agreement, a majority regime, exit protocols. And here’s a point that takes the pressure off the decision: moving between the two situations is trivial. An SLU brings in a partner through a simple transfer of quota shares (or a capital increase) and a declaration of loss of single-member status in a deed registered at the Commercial Registry; an S.L. becomes single-member by the reverse path. You’re not choosing forever. If your dilemma runs deeper structurally (projects aiming to go public, regulated sectors, large shareholder bases), then the relevant comparison is a different one, and we cover it in our guide on Sociedad Anónima vs Sociedad Limitada in Spain.

The SLU is, ultimately, the most efficient tool in Spanish law for going into business alone or landing a wholly owned subsidiary: all the power of the Sociedad Limitada, with no partners to coordinate, in exchange for a handful of transparency obligations that are met with basic documentary discipline. The key is respecting the regime’s three golden rules: register single-member status without running out the 6 months, document every contract between the shareholder and the company, and keep the separation of assets with the seriousness of someone who knows the shield only protects those who look after it. At ILLAY Legal we set up SLUs for entrepreneurs and foreign groups through fully online service, tying the incorporation together with the NIE, the self-employed work permit where applicable, and the tax planning of the shareholder’s compensation. Tell us about your project and we’ll tell you exactly how to structure it.

Frequently Asked Questions: Sociedad Limitada Unipersonal (SLU) in Spain