What "signing as attorney in fact" means
When you sign as attorney in fact, you are signing a document on behalf of someone else who has given you legal authority to do so through a power of attorney document. You do not sign your own name alone — you sign the principal's name (the person who gave you the power), then add your own name and your title as attorney in fact. This tells whoever receives the document that you had permission to sign it.
The signature format matters because it shows the document was signed under authority, not by the person themselves. Banks, title companies, and government offices will reject a signature that does not make this clear. How you sign depends on what type of power of attorney you hold and what document you are signing.
Key Takeaways
- Sign the principal's name first, then write "by" or a slash, then your name and title as attorney in fact — for example, "John Smith by Sarah Okafor, Attorney in Fact."
- Some institutions require you to show the original power of attorney document or a certified copy before they will accept your signature.
- A durable power of attorney remains valid even if the principal becomes incapacitated, but a regular power of attorney ends if they do.
- Different documents may have different signature requirements — real estate deeds often need notarization, while bank transactions may not.
- Keep a copy of the power of attorney with you when signing on behalf of the principal, because you may need to show it on the spot.
The correct signature format
The standard way to sign as attorney in fact is to write the principal's name, followed by "by," followed by your name and title. For example: "John Smith by Sarah Okafor, Attorney in Fact." Some institutions accept a slash instead of "by" — "John Smith / Sarah Okafor, Attorney in Fact" — but "by" is clearer and more widely recognized.
Do not sign only your own name. Do not sign the principal's name without adding your title. Either of these will cause the document to be rejected or questioned. The signature must show that you acted under authority, not on your own behalf.
If the document has a signature line with a printed title underneath, write your signature on the line and then write "Attorney in Fact" or "as Attorney in Fact" on or next to the title line. If there is no printed title line, add it yourself in parentheses or on the line below your signature.
When you need to show the power of attorney document
Banks, title companies, and government offices often require you to present the original power of attorney or a certified copy before accepting your signature. Some will make a photocopy for their records. Ask the institution in advance what they need — do not wait until you are at the signing.
If the power of attorney is old or the institution has never seen one before, they may ask their legal department to review it. This can add days to the process. Providing a certified copy (one stamped by a notary or court) moves things faster than an uncertified photocopy.
Keep the original power of attorney in a safe place and bring a certified copy with you when you sign documents on the principal's behalf. Some institutions will not return the copy, so make multiple certified copies if you will be signing many documents.
Durable versus regular power of attorney
A durable power of attorney remains valid even if the principal becomes mentally incapacitated or unable to manage their own affairs. A regular power of attorney ends automatically if the principal becomes incapacitated. This distinction matters because banks and other institutions may ask whether the power of attorney is durable before accepting your signature, especially if the principal is elderly or ill.
If you hold a regular power of attorney and the principal becomes incapacitated, you lose the authority to sign on their behalf. The principal or their family would need to go through a court process (guardianship or conservatorship) to give someone legal authority to act for them. If you are unsure whether your power of attorney is durable, check the document itself — it will say "durable" or "this power of attorney shall not be affected by the principal's incapacity."
Real estate and notarized documents
If you are signing a real estate deed, mortgage, or other document that requires notarization, you will need to sign in front of a notary public. The notary will watch you sign, check your identification, and stamp the document. You still use the same signature format — the principal's name, "by," your name, and "Attorney in Fact" — but the notary's seal makes it official.
Bring both your own identification and the power of attorney document to the notary. The notary will want to see proof that you are who you say you are and that you have the authority to sign. Some notaries will also want to see the principal's identification, though this is less common when the principal is not present.
Real estate transactions almost always require notarization. Bank documents, vehicle titles, and government forms vary — some require it, some do not. Ask the institution or agency before you sign.
What happens if you sign incorrectly
If you sign only your own name or only the principal's name without your title, the document may be rejected outright. The receiving institution may ask you to sign again in the correct format. If the document has already been filed or recorded, you may need to file an amended version or go through a correction process, which can delay transactions by weeks.
If you sign without having a valid power of attorney, or if the power of attorney has expired or been revoked, your signature has no legal force. The principal or the institution may challenge it later. Always verify that your power of attorney is current and covers the type of document you are signing before you put pen to paper.
Limits on what you can sign
A power of attorney document lists the powers you have. You might have authority to manage bank accounts but not to sell real estate. You might have authority to handle medical decisions but not financial ones. Before you sign anything, read the power of attorney and confirm that it gives you the specific power you need.
If the power of attorney does not cover what you are trying to do, signing anyway will not give you the authority to do it. The document will be invalid. If you need broader powers, the principal will need to sign a new or amended power of attorney that includes them.
Some powers of attorney are "general" (they cover almost everything) and some are "limited" (they cover only specific acts). Know which type you hold before you attempt to sign.
Frequently Asked Questions
Can I sign a check as attorney in fact?
Yes, if the power of attorney gives you authority over bank accounts. Sign it the same way: the principal's name, "by," your name, and "Attorney in Fact." Some banks require you to show the power of attorney the first time you deposit a check signed this way, but many do not. Call your bank in advance to ask what they need.
What if the principal is present when I sign?
You still sign as attorney in fact using the same format, even if the principal is in the room. The signature format shows that you are acting under authority, not that the principal is unable to sign. The principal does not need to co-sign unless the document or institution requires both signatures.
Does the power of attorney need to be notarized for my signature to be valid?
The power of attorney itself should be notarized when it is created, but that does not mean every document you sign as attorney in fact needs notarization. Real estate documents do. Bank documents usually do not. Check with the institution that will receive the document.
What if I make a mistake on the signature line?
Do not cross out and initial. Start over on a new copy of the document. Financial institutions and government agencies will not accept documents with crossed-out or initialed corrections on the signature line. If you have already signed incorrectly, ask for a new blank form and sign again.
Can someone else sign as attorney in fact if I give them permission?
No. Only the person named in the power of attorney document can sign as attorney in fact. You cannot delegate your authority to someone else unless the power of attorney specifically says you can. If you need someone else to sign, the principal will need to create a separate power of attorney naming that person.