Legal analysis: effective. No matter who wrote the IOU, it has legal effect as long as it conforms to the law and is signed or fingerprinted by the debtor. A loan contract shall be in written form, unless otherwise agreed between natural persons.

The contents of a loan contract generally include terms such as loan type, currency, purpose, amount, interest rate, term and repayment method.

Legal basis: Article 668 of the Civil Law of People's Republic of China (PRC) shall be in written form, unless otherwise agreed between natural persons.

The contents of a loan contract generally include terms such as loan type, currency, purpose, amount, interest rate, term and repayment method.

Article 465 of the Civil Code of People's Republic of China (PRC) * * * Contracts established according to law shall be protected by law.

A legally established contract is legally binding only on the parties, except as otherwise provided by law.