Email Signature Legal Requirements by Country: What Your Business Emails Must Include

By David, 2026-11-09, updated 2026-11-09

No law says "email signature", but company law in the UK, Ireland and the EU requires company details on business letters and correspondence, and Germany, Austria and Belgium say expressly that this covers electronic messages. In practice, a company's business emails there should show its registered name, legal form, registration number and register, and registered office, and in Germany and Ireland the names of its directors too. In the United States, Canada and for marketing email in the EU, the rules apply to commercial messages: who sent them, a postal address and a way to unsubscribe.

The short version: Put your company's full registered name, legal form, registration number, place of registration and registered office in the footer of every business email. Add the managing directors' names if you're a German GmbH or AG or an Irish company. If you mention share capital, state the paid-up figure. For marketing email, add a postal address and an unsubscribe link. This article is a summary, not legal advice: check the rules for your entity type with your own adviser.

Requirements at a glance

United Kingdom

The Companies Act 2006 and the Company, LLP and Business (Names and Trading Disclosures) Regulations 2015 set the rules.

• Registered name. It must appear on business letters, order forms, invoices, websites and, in the words of regulation 24, "all other forms of its business correspondence and documentation", which covers email.
• Particulars (regulation 25), on business letters, order forms and websites: the part of the UK where the company is registered (for example England and Wales), its registered number, and its registered office address. A company exempt from using "limited" in its name, and a community interest company that isn't a public company, must also say it's a limited company.
• Share capital. If you mention it, it must be the paid-up figure.
• Directors. You don't have to name directors, but if any director's name appears other than in the text or as the signatory, all of them must be named (regulation 26).
• Sole traders and partnerships trading under a business name must show the name of the owner or each partner and a UK address for service on business letters, orders, invoices and payment demands (Companies Act 2006 s1202).

Penalty: an offence by the company and every officer in default, with a fine up to level 3 on the standard scale and a daily default fine.

Ireland

Section 151 of the Companies Act 2014 requires, on all business letters and order forms: the company's name and legal form, its place of registration and registered number, and its registered office. On business letters that show the company's name, it also requires every director's forename (or initials) and surname, any former names, and nationality if not Irish. If share capital is mentioned, it must be the issued, paid-up figure, and the website must show the same company details. The section doesn't mention email by name, but most Irish companies treat business email as business letters. Penalty: a category 4 offence, with a fine of up to €5,000.

Germany

German law is explicit. HGB §37a, GmbHG §35a and AktG §80 all apply to business letters "of whatever form" addressed to a specific recipient, which includes email.

• Registered traders (HGB §37a): firm name, legal form, place of business, register court and register number.
• GmbH (GmbHG §35a): legal form and registered seat, register court and register number, and every managing director (Geschäftsführer), with surname and at least one forename written in full. If there's a supervisory board, its chair too. If capital is mentioned, the share capital and any outstanding contributions.
• AG (AktG §80): the same, with every management board member, the board chair identified as such, and the supervisory board chair.

Standard forms used within an existing business relationship are exempt, but order forms never are. Penalty: the register court can impose a coercive fine of up to €5,000.

Austria

UGB §14 applies to businesses entered in the Firmenbuch, on business letters and order forms "on paper or otherwise", and on their websites. They must show the firm name and legal form, seat, Firmenbuch number and Firmenbuch court. Capital companies that mention their capital must also state any outstanding contributions. (The old GmbHG §14 rule was repealed; UGB §14 is the one that applies.) Penalty: the register court can impose repeated coercive penalties of up to €3,600.

France

Article R123-237 of the Code de commerce requires registered businesses to show, on invoices, order forms, advertising and "all correspondence": their SIREN number, the letters "RCS" followed by the city of their registry, their registered office and, where relevant, that they're in liquidation. Article R123-238 adds that company documents must give the name with the legal form (or its initials) immediately before or after it, and, for a SARL or société par actions, the share capital. Penalty: a fourth-class contravention under R123-237.

Netherlands

Article 27 of the Handelsregisterwet 2007 requires registered businesses and legal entities to state their KvK number on letters, orders, invoices, quotations and other communications they send, except advertising. For a BV or NV, the Civil Code (Book 2, articles 186 and 75) also requires the full name and seat on all writings, and, if capital is mentioned, the issued and paid-up amounts. The law doesn't name email, but it's generally treated as covered.

Belgium

Article 2:20 of the Code des sociétés et des associations is one of the clearest: it applies to letters, order forms, websites and other documents "in electronic form or not". They must show the name, legal form, precise registered office, enterprise number, the letters "RPM" with the court of the registered office, the email address and website where relevant, and liquidation status. Penalty: a civil one. Under article 2:22, a person who commits the company on a document without these details can be held personally liable for that commitment.

Spain

Article 24 of the Código de Comercio requires registered traders and companies to show, on all documentation, correspondence, order notes and invoices, their domicile and their Registro Mercantil details, and for companies their legal form. If capital is mentioned, the subscribed and paid-up amounts. Businesses that provide online services also have to make their name, address, email, register details and tax number permanently available electronically under the LSSI (Law 34/2002, article 10); a website satisfies that.

Italy

Article 2250 of the Codice civile requires registered companies to show, in their documents and correspondence, their seat and their register office and number. An SpA, SApA or Srl must also show its capital as actually paid in, a single-shareholder SpA or Srl must say so, and a company in liquidation must say "in liquidazione". Companies with a public website must show the same information there.

Switzerland

Article 954a of the Code of Obligations requires the registered firm name to appear in full and unchanged in correspondence, order forms, invoices and announcements. A logo or short name can be used as well, but not instead. This article doesn't require a register number or address.

The EU rules underneath

Most of the national rules above implement Directive (EU) 2017/1132, article 26, which requires a company's letters and order forms, "whether they are in paper form or use any other medium", to state the register and company number, legal form, registered office and any winding-up, and requires the same on its website. Directive (EU) 2025/25 extends that article to certain partnerships, so expect national rules for partnerships to change as countries implement it.

Separately, the E-Commerce Directive (2000/31/EC) requires businesses providing online services to make their name, address, email, register number and VAT number available (article 5), and requires marketing messages to be clearly identifiable as such, along with who sent them (article 6).

United States

There's no US law that requires an email signature. The CAN-SPAM Act applies to commercial email, meaning messages whose main purpose is to advertise or promote, and requires:

• clear identification that the message is an advertisement (unless the recipient agreed to receive it);
• a working way to opt out;
• "a valid physical postal address of the sender", which can be a street address or a registered PO box or private mailbox.

Transactional and relationship messages are largely exempt, but the FTC says it reads those categories narrowly and that there's no exception for business-to-business email. Violations carry civil penalties per email, adjusted for inflation each year.

Canada

Canada's anti-spam law, CASL, applies to commercial electronic messages. Section 6 and the CRTC's regulations (SOR/2012-36) require the message to identify the sender and anyone it's sent for, give a mailing address and a phone number, email address or web address, and include an unsubscribe mechanism that stays valid for 60 days. If that isn't practical in the message itself, the details can be on a web page reached by a clear link. Penalties for businesses run to CAD 10 million per violation.

Australia

Section 153 of the Corporations Act 2001 requires a company's name to appear on its public documents, with its ACN (or its ABN, if the ABN contains the ACN) alongside. Public documents include business letters, statements of account, invoices, receipts and orders. ASIC's guidance doesn't mention email specifically, but treating business email as a business letter is the cautious reading.

What about confidentiality disclaimers?

None of the laws above requires the "this email is confidential" paragraph many companies add, and there's little case law on whether one protects you. If you keep one, keep it short, and don't let it crowd out the details the law does require. Put the required company details first.

Putting it into practice

• Write one compliant footer per legal entity, listing the details for its country. If you have entities in several countries, each needs its own.
• Apply it centrally, not by asking users. Signatures that people type themselves drift: details get deleted, out-of-date addresses survive, and new starters copy an old colleague's version.
• Decide whether every message must carry it. If yes, including mail from phones' built-in mail apps and other systems, you need a server-side layer, such as an Exchange Online mail flow rule. Our server-side vs client-side explainer covers the trade-offs.
• Review it when something changes: a new registered office, a new director in Germany or Ireland, or a new entity.

Atlas Ink, our signature product for Microsoft 365, handles the central part. Assign a template per entity with group scope, so each person gets the footer for the company they work for. Signatures are filled from Entra ID, and a daily reconcile puts back any signature a user edits or deletes. Templates keep a revision history, so you can show what a footer said on a given date. For users on clients a mailbox signature can't reach, optional server-side stamping adds the signature through a mail flow rule in your own Exchange Online; it isn't available in GCC or GCC High.

Here's the template list in our demo environment. It's the real Atlas Ink console; the templates are sample data:

For more on running signatures across a Microsoft 365 tenant, see our Microsoft 365 signature best practices and signature governance and precedence guides.

FAQ

Is an email signature legally required?

Not as such, but in the UK, Ireland and the EU, company law requires certain company details on business letters and correspondence, and Germany, Austria and Belgium say expressly that this includes email. The simplest way to comply is to put those details in every business email's signature or footer.

What must a UK company include in its business emails?

Its registered name, the part of the UK where it's registered, its registered number and its registered office address. If it mentions share capital, the figure must be paid-up capital, and if it names any director other than in the text or as the signatory, it must name all of them.

What must a German GmbH include in its emails?

Its legal form and registered seat, its register court and register number, and the names of all managing directors, with at least one forename written in full. If it has a supervisory board, the chair's name too.

Do US businesses need anything in their email signatures?

Not for ordinary business email. Commercial email under CAN-SPAM must include a valid physical postal address and a way to opt out, and must be identifiable as an advertisement unless the recipient agreed to receive it.

Is a VAT number required in an email signature?

Not by the general company law rules above. EU businesses providing online services must make their VAT number available under the E-Commerce Directive, usually on their website. Check local invoicing and tax rules for documents that are invoices.

Do confidentiality disclaimers have legal force?

None of these laws requires one, and there's little case law on whether they bind the recipient. They're a matter of company policy, not a legal requirement.

Last updated 9 November 2026. This article summarizes the law as published on official sites, checked on 9 November 2026. It isn't legal advice, and rules vary by entity type, so confirm with your own adviser. Sources: UK Companies Act 2006 s82 and s1202, SI 2015/17 reg 24, reg 25, reg 26 and reg 28, and GOV.UK guidance; Ireland Companies Act 2014 s151; Germany HGB §37a, GmbHG §35a and AktG §80; Austria UGB §14; France R123-237 and R123-238; Netherlands Handelsregisterwet 2007 and Civil Code Book 2; Belgium CSA; Spain Código de Comercio and LSSI; Italy Codice civile art 2250; Switzerland Code of Obligations; EU Directive 2017/1132, Directive 2025/25 and Directive 2000/31/EC; US 15 U.S.C. 7704 and the FTC CAN-SPAM guide; Canada CASL and SOR/2012-36; Australia ASIC on ACNs.