Protective letter: documents to prepare
A protective letter is a pre-emptive filing lodged with the competent court before a patent holder applies for an interim injunction. Preparing one means assembling prior art references, a claim chart, a statement of non-infringement or invalidity, and the corporate authorisation to file. The letter sits in the court's file and surfaces automatically once an injunction request arrives, without any separate hearing.
What the filing actually changes
Without a protective letter, a court asked for an urgent injunction can decide on the claimant's papers alone. With a letter already on file, the same court is expected to read both sides before ruling, even if no hearing takes place. The practical effect is a shift from a one-sided decision to a contested one, made on the same day the request lands.
The letter only works if it is filed before the request arrives. Once the court has already granted an injunction, submitting a letter cannot undo that order — it can only feed into a later challenge. That moment is the point of no return: after it, the file changes from prevention to appeal.
Documents to prepare
The set below covers what a court or its registry typically expects to find in a protective letter file. Missing pieces do not stop the filing, but they weaken the argument the letter is meant to carry.
| Document | Purpose | Who prepares it |
|---|---|---|
| Prior art search results | Supports an invalidity line if the claimant's patent is challenged | Patent attorney |
| Claim chart | Maps the product or process against the disputed claims, point by point | Patent attorney with technical input from the client |
| Non-infringement or invalidity statement | Sets out the legal position the court will read alongside any injunction request | Patent counsel |
| Corporate authorisation and power of attorney | Confirms who may file and act on the company's behalf | Company secretary or in-house legal |
| Technical description of the product or process | Gives the court a factual anchor independent of the claimant's framing | Product or R&D team |
If the anticipated dispute also touches online listings of the product, taking those down runs on a separate timetable with its own steps: Take-down and delisting procedure step by step in detail. The two filings do not replace one another.
Who decides, and on what timing
The decision sits with the division or panel of the competent court handling interim measures in patent matters. That body reviews the injunction request and the protective letter together once a request is filed; it does not rule on the letter by itself, since a letter with no injunction request behind it has nothing to decide.
No public schedule fixes how long a letter stays active or how quickly a court reviews a request once one is filed; both depend on the division's own caseload and are not published as a standard figure. What is fixed is the sequence: letter first, request second, joint review third. Filing after the request has already been decided removes the letter's purpose entirely.
The registry applies its own scale of charges for lodging the letter, published by the court rather than negotiated case by case. Preparing the file according to how our own practice is organised keeps the monitoring step consistent across matters: How the firm is set up in practice.
Two situations that call for different handling
If you sense a competitor building toward an infringement claim, file the protective letter before any request is lodged. Waiting until a claim letter arrives from the other side usually means the window has already closed.
If you are the one considering an injunction request, check the court's file first. A protective letter may already sit there, and finding it after filing your own request only slows down the response you were hoping for.
If the counterparty behind the anticipated claim is not who it appears to be, confirming control before filing anything changes the calculation: Counterparty in Sweden in practice sets out what that check can and cannot establish.
What this page does not cover
This page does not cover how to draft the underlying non-infringement opinion, how a court weighs conflicting claim charts, or how the procedure differs once the counterparty is served abroad rather than domestically — service across borders follows a separate track: Cross-border service of documents step by step. It also does not cover appeal routes once an injunction has already been granted; by that stage the point of no return has passed and a different set of steps applies.
Verified
Reviewed on the date this page was last updated. The description above reflects publicly available procedural guidance from the competent courts' own registries and internal file-handling practice; it does not rely on any single published figure for timing or cost, because none is fixed by rule.
Next step
A related risk sits one step earlier, before any dispute starts: When an agency keeps the design files and its ownership was never pinned down is worth checking before the file that matters leaves your hands. If a dispute is already forming, get the protective letter file moving first and confirm the counterparty second.
Frequently asked questions
How long does a protective letter take in practice?
No fixed period is published for review once a letter is on file. Drafting and filing typically take a few working days once the technical file — prior art, claim chart, non-infringement statement — is ready. The letter then stays active until withdrawn or until an injunction request forces a decision.
Which documents are needed to start?
The core set is a prior art summary, a claim chart, a non-infringement or invalidity statement, and corporate authorisation to file on the company's behalf. A technical description of the product rounds out the file and gives the court a factual reference independent of the other side's framing.
What happens if the other side does not respond?
Nothing is expected from the other side. The letter is filed for the court's benefit, not as a notice to the claimant, who may never see it unless an injunction request follows. If no such request arrives, the letter simply lapses or is renewed at the filer's discretion.