# What Is a National Security Letter (NSL)? | Kodex

Source: https://www.kodexglobal.com/glossary/national-security-letter

> A national security letter is an FBI demand issued without a judge. Learn what data it reaches, its secrecy rules, and how they can be challenged.

Compliance & Regulation

## National Security Letter (NSL)

A national security letter is an administrative demand issued by the FBI, without prior judicial approval, for limited subscriber and transactional records in national security investigations. It can carry a non-disclosure requirement, and it cannot compel the contents of communications.

Also known as
NSL

The national security letter is unusual in the set: compulsory, issued without a court, and historically accompanied by open-ended secrecy. Its scope has been narrowed substantially through litigation and legislation.

### What an NSL is

An administrative demand issued by the FBI under several statutory authorities, certifying that the records sought are relevant to an authorised national security investigation. No judge approves it in advance.

Its reach is limited by statute to categories including:

- Subscriber name and address

- Length of service and type of service provided

- Toll billing records or electronic communication transactional records

Content is outside NSL authority. Whether particular categories of modern metadata fall within “electronic communication transactional records” has been contested, and the FBI’s reading has at times been broader than providers and courts accepted.

### The secrecy problem, and how it changed

For years NSLs came with indefinite non-disclosure requirements and no clear route to challenge them. That drew sustained First Amendment litigation, and the USA FREEDOM Act introduced a reciprocal notice procedure requiring periodic review of whether secrecy remains necessary, plus judicial review on request.

NSL2703(d) order

Prior judicial approval None Required

Issued by The FBI A court

Reaches content No No

Built-in secrecy Yes, subject to review No, requires a separate order

Transparency reporting Banded ranges only Precise counts

### What it means for a company receiving one

- Check the demand against the statutory categories. An NSL asking for content or for records outside its authority should be narrowed, and providers have successfully pushed back on overbroad readings.

- Use the review procedures. Secrecy is reviewable, and recipients can trigger that review rather than treating the restriction as permanent.

- Report within the permitted bands. Precise counts are not permitted, and the banding rules are specific.

- Route these separately from criminal process. The authorities, the constraints, and the reporting rules all differ, and handling them in the same queue as ordinary subpoenas invites mistakes in both directions.

FAQ

### Frequently asked questions

Can a national security letter compel message content?

No. NSL authority is limited to specified categories of subscriber and transactional records: name, address, length of service, and toll billing or electronic communication transactional records. Content requires other process, and NSLs have at times been read more broadly than the statute supports.

Is the non-disclosure requirement permanent?

Not automatically. The USA FREEDOM Act of 2015 introduced procedures requiring the FBI to review whether continued secrecy is justified and allowing recipients to seek judicial review. Recipients can trigger review, and NSLs have been unsealed as a result.

How are NSLs counted in transparency reports?

Under restricted rules. Providers may report NSLs only in wide numerical bands rather than exact counts, and with a delay. This is why transparency reports show national security process in ranges while ordinary criminal process is reported precisely.

Glossary

### Related terms

#### Non-Disclosure Order

A non-disclosure order directs a company not to tell a user that their data was requested. It is a separate instrument from the process compelling production, is issued for a defined period, and requires the government to show that notice would cause a specific harm such as flight, evidence destruction, or danger to an individual.

#### 2703(d) Order

A 2703(d) order is a court order compelling a provider to disclose transactional records about an account. It requires specific and articulable facts showing the records are relevant to an investigation, which sits above a subpoena’s relevance standard but below a warrant’s probable cause.

NSL reporting follows special rules. See how Kodex supports transparency reporting.
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