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Avoid the Illegal Assignment of Workers
Illegal Assignment: A Real Risk You Can’t Afford to Ignore
On the MSC Blog – Avoid the Illegal Assignment of Workers.
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6 Keys to Avoid the Illegal Assignment of Workers
What Every Business Owner Should Know
In today’s business environment, where labor flexibility has become a strategic necessity, many companies turn to external services to meet their needs. However, what may initially seem like an efficient solution can quickly turn into a legal trap if not managed properly. We’re talking about a serious yet often misunderstood issue: the illegal assignment of workers.
Although it is not always done with bad intentions, illegal worker assignment is a serious violation of labor law. Its consequences can be devastating for both the supplying company and the company using the worker. Fines exceeding €180,000, joint liability for unpaid wages, social security contributions or compensations, and even prison sentences in the most severe cases, are just some of the potential outcomes of not preventing this risk.
Furthermore, both the supplying and the user company share responsibility, which makes it even more critical to have clear, transparent, and up-to-date information in order to avoid the illegal assignment of workers.
That’s why, in this article, we share 6 practical and easy-to-apply keys to help you prevent this problem. Through a professional and empathetic lens, we aim to support you in building sustainable, compliant, and legally sound working environments aligned with best practices.
Do your permanent employees earn more than the assigned personnel? This could be an illegal assignment.
➜ Understand What Illegal Assignment Really Means (and What It Doesn’t)
Illegal assignment of workers occurs when a company “lends” its employees to another company without complying with legal requirements. In other words, when workers formally hired by Company A are actually working under the direction, organisation, and supervision of Company B — as if they were its own employees.
This is completely different from a legitimate outsourcing of services. The key difference lies in who has effective control over the work. If your company is the one directing, supervising, and managing third-party personnel, you may be unknowingly committing an illegal assignment.
That’s why it is essential to carefully examine contracts and collaboration terms. It’s not enough to simply sign an agreement with a provider — you must ensure you’re acting in accordance with the law.
➜ Evaluate the Relationship Model: Service or Subordination?
One of the most important questions to ask in order to avoid illegal assignment of workers is:
Am I hiring a service, or am I managing people?
When you hire an external service, you should receive a result, not manage how, when, or with what tools the work is done. If you give direct instructions to external staff, if they use your equipment, follow your schedules, and integrate into your team as if they were internal employees, you are taking on a role of employer that legally does not belong to you.
This is where freelancers stand out as a clear, legal, and efficient alternative. Working with independent professionals means a direct relationship, without intermediaries, based on deliverables and objectives — not subordination.
➜ Choose to Collaborate with Freelancers
One of the safest ways to avoid the illegal assignment of workers is to choose freelancers instead of companies that “lend” personnel. Freelancers, by nature, work autonomously, manage their own schedules and resources, and are accountable for results — not presence.
They also bring agility, innovation, and specialisation to your projects. Most importantly, they significantly reduce the legal risk of falling into illegal assignment practices, since there’s no dependency or hierarchical relationship.
Of course, clear contracts, defined expectations, and professionalism are essential. But when properly managed, freelance collaboration is one of the safest and most beneficial ways to outsource work.
➜ Review the Structure of Your Contracts with Providers
To avoid the illegal assignment of workers, it’s critical to review not just who you hire, but how you do it. Contracts must clearly specify that you are hiring a service, not personnel.
Moreover, the provider company must have full autonomy in organising its resources. If you’re the one selecting staff, interviewing them, setting schedules, or integrating them into your internal systems, you may be crossing legal boundaries.
A key recommendation: Avoid vague clauses and regularly review your service contracts with legal counsel.
➜ Train Your Team on Legal Risks
Many employers engage in irregular practices simply out of lack of awareness. Hiring decisions are often delegated to middle managers or departments that aren’t legally trained, which can lead to costly mistakes.
To prevent illegal worker assignment, your teams (HR, procurement, operations) must understand what can and cannot be done when outsourcing.
Internal training sessions or professional legal advice can make a real difference and help protect your company from unnecessary sanctions.
➜ Watch for Red Flags
There are several indicators that should raise concern:
🔸 External staff work in your offices as if they were part of your team.
🔸 They use your equipment, uniforms, or corporate email.
🔸 They receive direct orders from your managers.
🔸 They follow a fixed schedule set by your company.
🔸 There is no clearly defined outcome in the service contract.
If one or more of these factors are present, you should review the relationship immediately before it leads to legal consequences.
Legal Basis of the Illegal Assignment of Workers in Spain:
1. Article 43 of the Workers’ Statute (ET)
This article stipulates that the hiring of workers to temporarily assign them to another company can only be carried out through duly authorized Temporary Employment Agencies (ETTs). Any other form of worker assignment outside this framework is illegal
➜ “The hiring of workers to temporarily assign them to another company may only be carried out by duly authorized temporary employment agencies.”
If one company hires another to provide workers, but in practice those workers are under the direction and control of the user company, the arrangement is presumed to be an illegal assignment
2. Joint Liability (also found in the Workers’ Statute and the General Social Security Law)
When illegal assignment is detected, both the assigning (cedente) and receiving (cesionaria) companies are jointly liable for labor and Social Security obligations towards the worker. In other words, the worker can demand their rights from either company
3. Sanctions – Law on Infractions and Sanctions in the Social Order (LISOS)
Illegal assignment is classified as a very serious offense, with fines ranging from:
🔸€7,501 to €225,018, depending on severity
🔸Additionally, the worker may be retroactively registered in the receiving company’s workforce, with seniority dated from the actual start of the assignment
4. Worker’s Right to Permanent Staff Status
A worker affected by illegal assignment has the right to choose to become a permanent employee of either the assigning or the receiving company. Their rights and obligations in the chosen company must be equivalent to those of a regular employee, with seniority counted from the start of the illegal assignment
Freelancers?
Spanish law does not specifically regulate “freelancers,” but they are classified as self-employed (autónomos), governed by:
🔸Law 20/2007, the Statute of Self-Employed Work (Estatuto del Trabajo Autónomo)
🔸General Social Security Law regarding contributions and affiliation.
Some may also qualify as TRADEs (Economically Dependent Self-Employed Workers) if 75% or more of their income comes from a single client, which imposes special obligations
⚠️ Important: Freelancers must provide a professional service with no dependency or subordination. If elements like fixed hours, supervision, or integration into your team are detected, the freelancer might be classified as a bogus self-employed (falso autónomo) — a practice that the labor inspection penalizes.
🛡️Freelancers: Legal, Efficient Collaboration Without Risks
When structured clearly, freelancers offer value, agility, innovation, and expertise without exposing your company to legal risks. As an employer, you must ensure that the relationship with freelancers avoids any semblance of hidden subordination.
Conclusion: Responsibility, Legality, and the Future
In short, avoiding the illegal assignment of workers is more than just a legal obligation—it’s a sign of commitment to transparency, regulatory compliance, and the well-being of all those involved.
As an entrepreneur, you have the power to reshape how you handle human and external resources. Choosing secure, collaborative models—like working with freelancers—not only mitigates risk but also adds value, efficiency, and sustainability to your operations.
We invite you to reflect on and review your labor relationships, not from fear, but from awareness, empathy, and responsibility.
Avoid the illegal assignment of workers. Protect your company. Strengthen your reputation. Embrace a more flexible, transparent, and lawful model.
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