Siga-an vs. Villanueva

No monetary interest shall be due unless it has been expressly stipulated in writing, and any interest paid pursuant to an oral or coerced agreement lacking such written stipulation must be returned pursuant to the principle of solutio indebiti.

Petitioner, a military officer and comptroller of the Philippine Navy Office (PNO), loaned respondent, a supplier dealing with the PNO, ₱540,000.00. No written agreement for the payment of interest was executed. Petitioner coerced respondent into paying interest by threatening to block or disapprove her PNO transactions, leveraging his authority as comptroller. Respondent issued checks and cash amounting to more than the principal. Petitioner later forced respondent to copy a promissory note acknowledging a larger debt inclusive of interest, which led to criminal charges for bouncing checks when respondent's subsequent checks were dishonored.

• The Loan Agreement: In 1992, petitioner loaned respondent ₱540,000.00. The agreement was not reduced to writing, and no stipulation regarding the payment of interest was made.
• Coerced Interest Payments: Respondent issued two checks totaling ₱700,000.00 as payment, creating an excess of ₱160,000.00. Petitioner demanded further interest payments, threatening to block respondent's PNO transactions. Fearing non-payment of her vouchers, respondent paid an additional ₱175,000.00 in cash. Petitioner refused to issue receipts for the cash payments.
• The Promissory Note: When respondent failed to pay further, petitioner required her to copy a promissory note dated September 12, 1994, acknowledging a debt of ₱1,240,000.00 inclusive of interest. Respondent issued six postdated checks to guarantee this obligation, but only one was honored.
• Criminal and Civil Actions: Petitioner filed five criminal cases for violation of Batas Pambansa Blg. 22 against respondent, resulting in her conviction. Respondent, upon being advised by counsel that interest was not due absent a written agreement, demanded the return of her overpayment. After petitioner ignored the demand, respondent filed a civil case for sum of money.

• Entitlement to Interest: Petitioner argued that he was entitled to monetary interest because both the RTC and CA found that he and respondent agreed on a 7% interest rate, which respondent allegedly admitted during the BP 22 cases. He maintained that Article 1956 should not be applied absolutely when the borrower admits a specific rate.
• Inapplicability of Solutio Indebiti: Petitioner maintained that solutio indebiti did not apply because respondent acknowledged her obligation inclusive of interest in the promissory note, precluding any claim of overpayment or mistake.

• Lack of Written Stipulation: Respondent countered that no written agreement for interest existed, rendering the collection of monetary interest illegal under Article 1956 of the Civil Code.
• Coercion and Mistake: Respondent argued that the interest payments and the promissory note were products of coercion and mistake, as petitioner leveraged his position as comptroller to force compliance.

• Monetary Interest: Whether petitioner is entitled to monetary interest on the loan despite the absence of a written stipulation.
• Solutio Indebiti: Whether the principle of solutio indebiti applies to the excess payments made by respondent.

• Monetary Interest: No monetary interest is due absent an express written stipulation. Article 1956 of the Civil Code requires the concurrence of an express stipulation and a written agreement for the payment of monetary interest. The promissory note was executed without true consent and under coercion, failing to satisfy the writing requirement. Respondent's alleged judicial admission of a 7% rate in the BP 22 cases did not establish the required written stipulation.
• Solutio Indebiti: The principle applies because respondent paid interest without a legal duty to do so, and such payment was made through mistake. Petitioner was unjustly enriched, obligating him to return the proven excess amount of ₱335,000.00 (comprising the ₱160,000.00 excess from the checks and the ₱175,000.00 cash payment admitted in petitioner's reply-affidavit).

• Solutio Indebiti — Arises when (1) a payment is made when there is no binding relation between the payor and the payee, such that the payor has no duty to pay, and (2) the payment is made through mistake, not liberality. Applied to the erroneous payment of interest where no written stipulation exists, creating a quasi-contractual obligation to return the unduly paid amount.
• Monetary Interest vs. Compensatory Interest — Monetary interest is compensation fixed by the parties for the use or forbearance of money and requires an express written stipulation. Compensatory interest is imposed by law as penalty or indemnity for damages (e.g., for delay under Art. 2209) and does not require a written stipulation, but cannot be charged as compensation for the use of money absent such stipulation.

• "Article 1956 of the Civil Code, which refers to monetary interest, specifically mandates that no interest shall be due unless it has been expressly stipulated in writing."
• "Under Article 1960 of the Civil Code, if the borrower of loan pays interest when there has been no stipulation therefor, the provisions of the Civil Code concerning solutio indebiti shall be applied."

• Eastern Shipping Lines, Inc. v. Court of Appeals — Followed regarding the proper computation of legal interest: 6% per annum for obligations not constituting a loan or forbearance of money from extrajudicial demand until finality, and 12% per annum from finality until satisfaction.
• Ching v. Nicdao; Tan v. Valdehueza — Followed in reiterating that the collection of interest without a written stipulation is prohibited by law.
• Moreño-Lentfer v. Wolff — Followed in defining the requisites of solutio indebiti.
• Velez v. Balzarza — Followed in applying solutio indebiti to the erroneous payment of undue interest.

• Article 1956, Civil Code — Applied to bar the collection of monetary interest absent a written stipulation.
• Article 1960, Civil Code — Applied to subject the payment of interest without stipulation to the rules on solutio indebiti.
• Article 2154, Civil Code — Applied to define the obligation to return something received when there is no right to demand it.
• Articles 2209, 2212, Civil Code — Cited to distinguish compensatory interest from monetary interest.
• Articles 2216, 2217, 2232, Civil Code — Applied to justify and calibrate the awards for moral and exemplary damages.

Consuelo Ynares-Santiago, Ma. Alicia Austria-Martinez, Antonio Eduardo B. Nachura, Teresita J. Leonardo-De Castro