One of the aspects many companies overlook when defining their patent strategy is where to file the first patent application.

Some choose based on available grants or financial aids; others according to the location of their parent company or corporate headquarters; and others also consider factors such as where the invention was developed, the nationality or residence of the applicant and/or inventors, and even the content of the application.

However, in many cases, while these factors influence the choice of where to make the first filing, the legal obligations and potential consequences of not complying with them are not always fully considered.

 

Why does it matter?

In Spain, before the current Patent Law, it was not entirely clear what the consequences were for first filing abroad an invention developed in Spain. The obligation existed, but the law did not specify what would happen if it was not fulfilled.

With the Spanish Patent Act 24/2015, the consequences are now explicit: If a patent application for an invention developed in Spain is first filed abroad without having been previously filed at the Spanish Patent and Trademark Office (OEPM) or without obtaining the corresponding Foreign Filing License (FFL), you may ultimately lose the ability to secure protection in Spain. This includes the potential loss of effect of a European patent validation in Spain or of the national phase entry in Spain of a PCT application.

 

A common requirement in other countries

First-filing requirements were established to protect national security and control the disclosure of sensitive technologies abroad. Their main objectives are to prevent the dissemination of inventions with defense or strategic value, retain technological knowledge within national borders, and enable patent offices to review innovations that may require secrecy restrictions.

This concept has long been embedded within the broader framework of international agreements aimed at safeguarding national security and the economic interests of states through the patent system. For instance, the NATO Agreement for the Mutual Safeguarding of Secrecy of Inventions Relating to Defence coordinated the protection of defense-related inventions among member states — including Spain, France, the United Kingdom, Germany, and the United States — ensuring the confidential handling of classified patent applications. Similarly, other international instruments such as the TRIPS Agreement, the Patent Law Treaty (PLT), or the Patent Cooperation Treaty (PCT) expressly recognize the right of each contracting party to adopt secrecy measures and impose restrictions on patent filings for reasons of national security or essential interests.

Over time, this framework has been implemented and maintained across jurisdictions with the same purpose, with the first-filing obligation forming part of these measures. Many national patent regulations establish it based on criteria such as the applicant’s nationality, the inventors’ nationality, whether the invention was developed domestically, and/or whether the content of the application is considered sensitive under secrecy-related local rules.

In some jurisdictions, failure to comply may result in administrative or even criminal sanctions, as well as the loss of patent rights or the inability to obtain protection, with the specific consequences depending on the applicable national regulations and the nature of the invention.

Nevertheless, many systems provide a mechanism known as the Foreign Filing License (FFL): an authorization that allows the first filing to be made abroad while ensuring compliance with local regulations.

 

Increasingly complex scenarios

In practice, these requirements are especially relevant in contexts involving international collaborations, multinational R&D teams, or applicants/inventors from different jurisdictions.

In such cases, your patent attorney can help you define the best strategy, taking into account not only commercialization and potential disclosures (for timing purposes) but also the legal restrictions on first filing.

 

The Spanish case and a practical comparison with the US

As mentioned, Spanish law provides that if an invention was made in Spain, the first filing must be made at the OEPM, unless an FFL has been obtained. There is also a rebuttable presumption (iuris tantum) that an invention was developed in Spain if the applicant is domiciled there. Therefore, the obligation depends not on the inventor’s nationality or residence, but on where the invention was developed.

Getting an FFL from the OEPM is a simple and fast procedure. Once granted, you can file the patent abroad without compromising future protection in Spain.

The United States applies a similar system: the first filing requirement is based on where the invention was made, and the U.S. Patent and Trademark Office (USPTO) also issues FFLs for applicants wishing to file first outside the country. The process is also straightforward and typically completed within a few days.

 

Example

Conclusion

  • When planning your international patent strategy, evaluate early on the FFL or first-filing requirements to avoid losing effects in key markets or facing more serious consequences such as administrative or criminal sanctions.
  • Work with a qualified patent attorney who understands the pitfalls of each jurisdiction and can assist you in analyzing and validating your filing strategy.