1 is illegal. If there is evidence that it is a forged customer signature, it is a fraudulent contract. Of course, it is invalid, and you can even sue for fraud. If it is a loan, the forged signature will be exempted; If it is counter business, there are two kinds: deposit and withdrawal. After the deposit, the bank can report to the banking regulatory bureau if it forges the customer's signature. If it is a withdrawal, the bank can apply for civil compensation by forging the customer's signature.

2. Legal basis: Article 153rd of the Civil Code of People's Republic of China (PRC).

A civil juristic act that violates the mandatory provisions of laws and administrative regulations is invalid. However, unless mandatory provisions do not invalidate civil legal acts. A civil legal act that violates public order and good customs is invalid.

Second, what is the crime of forging others' signatures?

Forging someone else's signature constitutes fraud. If it is used to make perjury, it constitutes perjury. If it is used to forge government documents, the circumstances are even more serious. Signature has legal effect, and forged signature bears legal responsibility. However, just forging a signature does not constitute a criminal offence, and it is necessary to comprehensively judge whether it constitutes a crime and what kind of crime it constitutes by combining the specific behavior, social harm and harmful consequences after forgery.

3. Is the forged signature contract effective?

Not established, because signing a contract involves illegal behavior. Contract fraud may constitute the crime of contract fraud, and if criminal responsibility is required, it shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention, and shall also or only be fined.