Not if they actually gave you authority to sign. Forgery by false signature requires proof that you did not have authority to sign the name, that you knew you did not have it, and that you intended to defraud. If the person now denies giving permission, the prosecution still has to prove each of those points, including what you knew when you signed.

The elements

California’s forgery-by-signature law, Penal Code section 470(a), applies to a person who, with intent to defraud and knowing they have no authority to do so, signs the name of another person or of a fictitious person to one of the documents the statute lists, such as a check, a contract, a receipt, a power of attorney, or a vehicle ownership certificate. CALCRIM No. 1900, the jury instruction for this charge, breaks it into four elements the prosecution must prove: you signed someone else’s name, or a false name, to a listed document; you did not have authority to sign that name; you knew you did not have that authority; and when you signed, you intended to defraud. If any one of them is not proved, the jury cannot convict on this charge.

Where permission fits

Permission goes to two of those elements. If the person really authorized you to sign, the second element fails. If they now deny it, the jury decides whether you had authority, and the prosecution must also prove that you knew you did not. A genuine belief that you had permission bears directly on that knowledge element, although the prosecution can still try to prove from other evidence that you knew otherwise. A denial that surfaces after the fact does not, by itself, prove what you knew when you signed.

Practically, the questions will be what exactly the person allowed you to sign and whether this document was within that permission.

What counts as intent to defraud

Under CALCRIM No. 1900, intent to defraud means intending to deceive someone in order to cause them a loss of money, goods, services, or other value, or to damage a legal, financial, or property right. The instruction adds that no one has to have been actually defrauded or to have actually suffered a loss (CALCRIM No. 1900). So pointing out that nobody was harmed does not answer the charge by itself; the question is still what you intended and knew when you signed.

Evidence of permission

The case turns on what you knew when you signed, so the most useful evidence is what already existed at that time:

  • Texts, emails, or other messages where permission was discussed
  • A history of signing for that person before, without objection
  • Any written authorization that already exists, such as a power of attorney or an account authorization naming you
  • People who were present when permission was given

Give these to your lawyer as they are. Do not create a new authorization after the fact, and never backdate a document or present it as older than it is.

Altered or counterfeit documents

Falsely making or altering a document, passing a forged one, or counterfeiting someone’s handwriting or seal is covered by other parts of Penal Code section 470, with different elements; see the firm’s forgery overview.

Getting help

Whether a signature dispute becomes a forgery case often comes down to the communications and history between you and the other person, not just their current account. Call (800) 755-5174 to go over the facts with the Law Offices of David S. Chesley.