Trade secret protection and employee mobility: step by step means securing evidence of what a departing employee knew and used, locking down system access once notice is given, warning the new employer in writing, and choosing between a cease-and-desist letter, an interim injunction, or a damages claim once misuse can be shown under Swedish law as it currently stands.
Who this concerns
This sequence applies whenever a company that holds technical drawings, pricing models, customer lists, source code, or process know-how is about to lose an employee who had access to that material. It applies equally to the employee leaving for a direct competitor, the employee starting a competing business, and the employee moving to a supplier or customer that now sits closer to the company's own commercial position.
The trigger is rarely the resignation letter itself. It is the pattern that follows it: unusual file downloads in the weeks before notice, a sudden interest in a specific customer folder, a personal device connected to the company network, or a new employer whose product roadmap looks familiar within months of the hire. None of that is proof on its own. It is the reason the sequence below starts before the employee has physically left the building.
The practice sits within our broader intellectual property and UPC practice, because the same evidentiary discipline that protects a trade secret is what a patent or design dispute needs when the underlying know-how never made it into a registered right.
What the law says
Under Swedish law as it currently stands, a trade secret is information that is not generally known or readily accessible, that has commercial value because of its secrecy, and that the holder has taken reasonable measures to keep secret. All three elements have to be argued together. A company that never restricted access to a document, never marked it as confidential, and never limited who could copy it will struggle to call that document a trade secret later, however commercially sensitive it looks in hindsight.
The framework gives the holder of a trade secret civil remedies against a person who acquires, uses, or discloses it without consent, and against a third party who knew or should have known that the information came from an unlawful source. That second limb is what makes the new employer a legitimate target of a warning letter, not only the former employee. Deliberate misuse can also carry criminal exposure, which runs on a separate track from the civil claim and does not replace it.
Where the employee relocates to another EU or EEA state, or where the new employer is a foreign group entity, the underlying trade secret regime is harmonised in substance across the internal market, but enforcement, evidence gathering, and interim relief still run through the courts of the state where the misuse occurs or where the defendant is domiciled. A Swedish injunction does not automatically freeze activity abroad; a parallel or recognised order in the relevant jurisdiction is usually required before an evidence.
How it works in practice
Step 1: Confirm what actually qualifies before the employee leaves
Before any letter goes out, list the specific documents, files, or knowledge at stake and check each one against the three-part test above. Generic "experience" and "industry knowledge" the employee built up over the years is not a trade secret and cannot be treated as one. A pricing algorithm, an unpublished formulation, or a structured customer database usually is, provided access to it was actually restricted.
Step 2: Freeze and record access at the moment notice is given
From the day notice is received, restrict and log the employee's access to systems containing the material identified in Step 1. Record what was downloaded, printed, or emailed in the preceding months, not only from the notice date forward. Evidence gathered after the employee has left is far weaker than evidence secured while access could still be monitored in real time.
Step 3: Handle the notice period as a controlled window, not a formality
During notice, decide whether the employee continues in the role, moves to different duties, or is placed on paid leave for the remainder of the period. Continued access to the sensitive material during notice without any adjustment is one of the most common reasons a later claim fails: the company cannot argue the information was tightly controlled if the departing employee kept full access until the last working day.
Step 4: Conduct an exit review before the final day
On or before the last working day, review devices, cloud storage, and personal accounts that had access to company systems, within the limits set by data protection and employment rules. Collect a signed confirmation that all copies of confidential material have been returned or deleted. This document becomes central evidence if a dispute follows.
Step 5: Assess the new employer's exposure separately from the employee's
If the destination is a known competitor or a business the employee is starting, assess independently whether that entity is likely to receive or use the material. This assessment determines whether the new employer becomes a direct addressee of a warning letter alongside the employee, which materially increases pressure to resolve the matter without litigation.
Step 6: Send a documented warning before escalating
A written warning to the employee and, where warranted, to the new employer, sets out what information is at risk, what conduct would constitute misuse, and what is expected going forward. It also creates the evidentiary record showing the recipient was on notice, which matters for the third-party liability point described above if misuse is later discovered.
Step 7: Choose the enforcement track once conduct crosses the line
If misuse can be shown or is imminent, the available tracks are an interim injunction to stop ongoing use, a claim for damages measured against the harm caused or the gain obtained by the other side, or a combination of both. The choice depends on whether the priority is stopping active use immediately or recovering the commercial loss, since the evidentiary bar and the practical urgency differ between the two.
Step 8: Preserve the claim if the matter goes to court
Where litigation follows, the file built in Steps 2 to 6 becomes the backbone of the case: access logs, the signed exit confirmation, the warning letter, and any response from the employee or the new employer. Gaps in that file, particularly around the notice period, are what typically weaken an otherwise strong claim.
What to check before deciding how to proceed
- Whether the material at stake meets all three elements of a trade secret, not only the commercial value element.
- Whether access to that material was actually restricted before notice was given, not only in policy but in system configuration.
- Whether the employment contract or a separate confidentiality undertaking addresses post-employment use of the material, and whether that clause is broad enough to cover the conduct now observed.
- Whether the destination employer is a group entity, a direct competitor, or an unrelated third party, since this changes who the warning letter should address.
- Whether any cross-border element is present, and if so, in which jurisdiction interim relief would actually need to be sought to have practical effect.
The numbers
There is no fixed statutory countdown that applies uniformly to every case in this sequence. The length of the notice period comes from the individual employment contract or the applicable collective agreement, not from a general rule, and it varies accordingly. The time available to secure evidence is set in practice by how quickly the exit review in Step 4 is carried out relative to the last working day, not by a deadline in the framework itself.
Court timelines for an interim injunction application depend on the caseload of the specific court and on how complete the supporting evidence is at filing. A file that already contains access logs, the signed exit confirmation, and the warning letter moves faster through the interim stage than one assembled after the fact, but neither situation carries a guaranteed number of weeks.
Where damages are pursued, the amount depends on how the loss or the gain is measured on the facts of the specific case rather than on a set formula, and it is not something that can be stated as a range in the abstract before the underlying figures are known.
Where it usually goes wrong
The claim collapses most often at Step 1, not at the litigation stage. Companies frequently treat broad categories of information, such as "our process" or "our client relationships", as protected without being able to point to a specific document or dataset that was actually restricted. A court asked to enforce a trade secret needs a defined object, not a description of the business as a whole.
The second common failure is inconsistent access control. If the same sensitive file was accessible to twenty employees without a confidentiality marking, without a restricted folder, and without any exit procedure applied to previous departures, arguing that this particular departure warrants protection is difficult, because the holder cannot show it treated the information as secret in practice.
General skills, professional judgment, and industry contacts the employee built up while employed are not trade secrets and cannot be restrained through this route, however commercially valuable they are to the new employer. Attempts to use a trade secret claim to prevent an employee from competing at all, rather than to prevent the specific misuse of specific information, tend to fail and can undermine the credibility of the genuine part of the claim.
Finally, delay is corrosive. A company that waits months after discovering suspicious activity before sending a warning letter or applying for interim relief weakens its own argument that the use was urgent enough to justify an injunction, and it gives the other side time to argue that any harm has already occurred and cannot be undone by a court order.
If suppliers or subcontractors also had access to the same material
Where subcontractors or suppliers handled the same sensitive files as the departing employee, the analysis in security requirements on suppliers and subcontractors sets out what contractual and technical controls should already be in place before an employee departure ever becomes an issue.
If the departure follows an acquisition
Where the employee leaving coincides with a business sale that included an earn-out mechanism, the loss of key know-how can also feed into a post-completion dispute. Earn-out disputes after closing covers how evidence of that kind is preserved when the underlying commercial performance is contested.
If the company holding the trade secret is itself under financial pressure
A trade secret claim pursued while the claimant company is heading toward insolvency raises separate questions about who controls the litigation and the underlying rights. A creditor's bankruptcy petition sets out the terms that apply once that stage is reached.
What to do next
This sequence covers what a company can organise on its own: identifying what actually qualifies, controlling access, documenting the exit, and choosing between a warning letter, an injunction, and a damages claim. Where the analysis genuinely stops is the point where the evidence needs to be assessed against the specific facts, the contract wording needs to be tested for enforceability, and a decision needs to be made on whether to escalate at all.
That is the point of an assessment call: reviewing the specific documents, the access records, and the contractual clauses at stake to determine whether the claim is strong enough to warrant a warning letter, an injunction application, or neither. Book an assessment once the internal steps above have been completed.
Where the underlying dispute concerns ownership of software rather than misuse of confidential information, the separate question of who owns the code is addressed in copyright in commissioned software, which sets out how that ownership question is resolved when no assignment was documented at the outset.
Frequently asked questions
What security requirements should apply to suppliers and subcontractors who received the same sensitive material as the departing employee?
The starting point is the same as for employees: restrict access to what is strictly necessary, mark the material as confidential, and set out post-contract obligations in writing. Details are set out in security requirements on suppliers and subcontractors, which addresses evidence preservation specifically for third-party access rather than employment relationships.
Can the loss of key know-how through employee departure also affect an earn-out calculation after a sale?
Yes, where the departing employee held know-how that underpinned the performance metrics an earn-out was based on. The commercial and evidentiary issues that arise once completion has occurred are addressed in earn-out disputes after closing.
What happens to a trade secret claim if the company bringing it becomes insolvent during the dispute?
Control over the claim can shift to an insolvency administrator, and the terms on which a creditor can bring a bankruptcy petition become relevant to how the underlying dispute proceeds. This is covered in a creditor's bankruptcy petition.
About the author
Frida Norell leads intellectual property and UPC matters at Lodline, with a focus on the practical evidentiary work behind trade secret and technology disputes rather than registration filings alone.