Short answer. The sale price — or the right to collect it. Under Article 2160, a good-faith payee who received an undue payment of a specific item and then sold it must return the price they received for it, or, if the price is still uncollected, assign the action to collect that sum to the person entitled to the item.
What the law says
If he has alienated it, he shall return the price or assign the action to collect the sum.
Civil Code, Article 2160 — Good-Faith Payee. Read the full provision →
The undue payment of a specific thing
Undue payment — paying what is not owed — can involve money or it can involve delivering a specific, determinate object. When a specific item is delivered by mistake, the recipient who genuinely believed it was rightfully theirs is treated as a good-faith payee under Article 2160. The law distinguishes between a payee who still has the item and one who has already sold it, because the remedies available differ significantly depending on what happened to the item after it was received.
What must be returned after a sale
If the good-faith payee already sold the item before learning the payment was undue, they cannot return the item itself — it belongs to a third party who may well have their own rights. Article 2160 substitutes a monetary obligation: the payee must return the price they received for the sale. This tracks the actual benefit the payee obtained from the item. Selling the item converted it into money, and that money is what the payee must now hand over to the person who was wrongly deprived of the item.
When the price has not yet been paid
If the payee sold the item on credit and has not yet collected the price, there is no cash to return. Article 2160 handles this with an alternative: the payee assigns the action to collect the sum — that is, they transfer the right to sue the buyer for the unpaid price. The person entitled to the item steps into the payee's shoes as creditor. This ensures the obligor's obligation to make whole is not frustrated simply because the sale price is still outstanding at the time the error is discovered.
Why good faith matters here
Article 2160 specifically protects a payee who received the item in good faith — genuinely believing the payment was due. A bad-faith payee, who knew the payment was undue but accepted it anyway, faces a more onerous set of obligations under the Civil Code's rules on solutio indebiti. Good faith limits the payee's exposure to what they actually received or benefited from: the sale price, or the right to collect it. The law does not impose further penalties on someone who acted honestly and simply needs to restore the economic equivalent of what they wrongly but innocently received.
Cases citing this provision
These Supreme Court decisions cite the provision above. We list them so you can read them yourself; the summaries of what each decided are not ours to give.
- Titan-Ikeda Construction and Development Corp. vs. Primetown Property Group, Inc, G.R. No. 158768, February 12, 2008 — read the decision on LawPhil →