Signing on Behalf of Someone: Rules, p.p. & Liability

Signing a document "on behalf of" someone else is more than a courtesy line above a signature. It has direct legal consequences and can determine whether a document binds the person or company you are representing – or binds you personally. A defect in the authority, or the wrong notation next to your name, can leave a statement unenforceable or expose you to liability. In companies, agencies and other organisations, drawing a clear line between the different kinds of authority is essential to avoid misunderstandings and legal risk.

This guide explains the legal basis and the practical requirements for signing on behalf of another person. It covers the difference between "p.p." (per procurationem) and the "for and on behalf of" format, who is actually entitled to sign, and what happens when an authorisation is missing or wrong. It also offers practical tips to make sure authority is granted correctly and can be proven later.

The legal basis: who can sign on behalf of someone?

Signing in the name of another person or a company is common in legal, commercial and administrative life. But who is actually allowed to do it? The answer lies in the law of agency – the body of rules that lets one person (the agent) act so as to bind another (the principal). The same logic applies under both common-law and civil-law systems, even though the terminology differs.

Agency: acting in another's name

The core principle is simple: where an agent acts within the scope of their authority and makes clear that they are acting for a principal, the resulting agreement binds the principal, not the agent. The agent is merely the conduit. Everything turns on two things – that authority actually exists, and that the signature makes the representative capacity clear.

Types of authority

1. Express authority: The principal has explicitly granted the right to act – for example in an employment contract, a board resolution or a power of attorney.
2. Implied authority: Authority that follows naturally from a person's role. A purchasing manager can usually place orders within their remit without a separate mandate for each one.
3. Apparent (ostensible) authority: Where the principal's conduct leads a third party to reasonably believe the agent is authorised, the principal may be bound even if no actual authority was given.
4. Specific authority: Granted for a single transaction or act – for example selling one particular asset or attending one negotiation.

Form of authority

• Authority can usually be granted orally or in writing.
• For certain transactions, the law requires writing (and sometimes a deed or notarisation).
• Where the underlying transaction must be executed as a deed (for example some real-estate dealings), the authority typically has to be granted in the same form.

Lack of, or defective, authority

Where someone acts without valid authority:

• The statement is generally unenforceable unless and until the principal ratifies it after the fact.
• If ratification is refused, the statement has no legal effect.

This can cause serious legal and commercial problems, particularly when a contract has already been concluded on the strength of the signature.

Personal liability

If a person signs without authority – or beyond it – they can be held personally liable to the other side for the loss caused, especially where they knew, or ought to have known, that their authority was insufficient. The supposed principal walks away; the signatory is left holding the obligation.

Relevance for companies and organisations

Companies and public bodies should put measures in place to ensure that only authorised people sign:

• Issue written authorisations.
• Keep a central register of the authorities granted.
• Train staff regularly, especially on new roles or after promotions.
• Use digital systems to manage and monitor authority.

Missing internal rules can lead to unenforceable contracts, internal disputes and legal liability.

How should you sign on behalf of someone?

A clear, correct and properly authorised signature is essential to avoid legal problems and delays. It confirms that the signatory is acting in the name of another person and not in their own name. Missing or unclear authorisation can render the signature invalid and expose the signatory to personal liability.

Common ways to sign on behalf of someone:

• "p.p." (per procurationem): Signals that you are signing on behalf of a named person, typically in letters and correspondence. The convention places "p.p." before the name of the person physically signing. Example: p.p. Jane Smith under the name of the absent manager – Jane signs the letter on her manager's behalf.
• "for and on behalf of [Company]": The standard wording for executing a document as a company's authorised representative. The company is named, followed by the signatory's signature, name and title. It makes clear the obligation is the company's, not the individual's.
• The "By: / Its:" execution block: Common in US corporate documents. The company name is stated, then a line for By: (the signature and printed name) and Its: (the signatory's office, e.g. "Its: Chief Financial Officer").

Whose name do you write when signing p.p.?

One of the most common points of confusion: do you write your own name or the other person's? The answer is clear – when you sign "p.p.", you write your own name, not that of the person or company you represent. The notation sits immediately before your own name:

p.p. Jane Smith

That way everyone can see that Jane Smith is making the statement on behalf of someone else and is not becoming a party herself. The same logic applies to the "for and on behalf of" format: the company is named, and the individual signs as its representative, stating their title.

Signature requirements and legal validity

Handwritten signatures: Often required by law or contract – particularly for deeds, guarantees or notarised documents. Tip: When in doubt, sign by hand and keep a copy.

Electronic signatures: An electronic signature is valid under the EU's eIDAS Regulation and, in the US, the ESIGN Act and UETA – but it should:

• Meet the required assurance level (for example an advanced or qualified electronic signature).
• Be checked against the specific document type where there is any doubt.

Defective or unauthorised signatures:

• Can render a document legally ineffective.
• Can be rejected by the principal or challenged by third parties.
• Can lead to personal liability for the signatory.

Risks and liability when signing on behalf of someone

Signing on behalf of another is not just a formality – mistakes or misuse can have serious consequences. Anyone who signs a document without sufficient authority, or mislabels their representative capacity, can become liable. Both the signatory and the principal should be aware of the risks.

Liability of the agent for a defective signature

• Where a signature is made without valid authority, the signatory may be personally liable – meaning they themselves must perform the obligations in the document if the supposed principal does not ratify it.
• If authority was wrongly documented or exceeded, that too can lead to personal liability. It matters whether the agent knew, or ought to have known, that their authority was insufficient.
• Even careless mistakes – for example signing in a way that overstates your authority – can leave you liable for any resulting loss.

Can an authorisation be challenged after the fact?

• An authorisation can, in certain circumstances, be revoked or disputed – especially where it was based on incorrect information or the principal was unaware of its legal effect.
• If authority has been revoked, that must be communicated clearly to the relevant parties. Otherwise a third party may act in good faith on authority that no longer exists.
• Where authority was obtained by deception or mistake, it can be challenged under the general law.

Examples of misuse or defective authority

• An employee signs a contract on their own initiative, claiming to act on behalf of management. The contract is challenged because no valid authority existed.
• An assistant signs a payment instruction "p.p.", although they were only authorised to forward it, not to issue binding payment orders. The payment is not recognised and a loss results.
• A representative relies on an earlier authorisation despite being told internally that it had been revoked. Because this was not communicated to third parties, a dispute follows.

To avoid such problems, companies and public bodies should set clear rules for handling authority – including regular review and documentation of the powers granted, and making staff aware of the liability risks.

Practical tips for granting and using authority to sign

A clear, documented authorisation process is essential to avoid legal uncertainty and potential liability. Anyone signing documents on behalf of a company or organisation should know not only the exact scope of their own authority, but also that the necessary evidence is correctly on file. Inadequate clarity about authority is a problem not just for the signatory, but also for the organisation that has to rely on the validity of the statement later.

What to check before you sign "p.p."

Before signing "p.p.", make sure you genuinely have valid, documented authority. If there is no clear rule, or it was given only orally, uncertainty and legal problems can follow. Check, too, that the authority is sufficient for this act – many organisations set different levels of authority, and signing beyond yours can leave you facing the liability question if a dispute arises.

Equally important is the correct wording and notation. "p.p." signals that you are simply signing on someone's behalf, whereas "for and on behalf of" executes a document as a company's representative. This distinction matters to avoid confusion with internal and external parties. When in doubt, check with your manager or legal team before signing.

How to make the authority legally sound

For an authorisation to be binding and verifiable, it should be in writing. An oral arrangement may suffice in some cases, but it offers no reliable protection if a dispute arises. For business-critical decisions in particular, it is advisable to have a written authority that sets out precisely which acts are permitted and which are not.

It is also important to keep authorisations up to date. People change roles, responsibilities shift and company policies are revised. To be sure an authority is still valid, review it regularly against current requirements. Companies and public bodies should have clear processes to manage and document authority. For broad commercial authority, a formal commercial power of attorney may be the right instrument.

Where there is any uncertainty, involve the legal team or a manager before signing – especially for complex or financially significant transactions, where an extra review can reduce legal risk.

Which records should you keep as evidence?

To be protected in a dispute or an internal or external audit, keep certain documents and evidence to hand:

• Authorisations granted: A written copy of the authority is essential. It should state the exact powers and the period of validity, and be signed by both parties.
• Correspondence about the authority: Emails or written instructions can serve as proof of an authority granted or revoked.
• Signed documents: A complete record of everything signed ensures there are no later questions about the signatory's authority.
• Changes or revocations: If an authority is changed or revoked, record it in writing and communicate it clearly. Notifying all relevant parties is essential to avoid later misunderstandings.

Filing these records systematically helps establish clarity quickly, both in internal reviews and external disputes. In larger organisations especially, where several people hold different kinds of authority, a transparent evidence trail is an indispensable element of acting with legal certainty.