Short answer. It can be. Article 315 covers misappropriating or converting, to the prejudice of another, money or property received in trust, on commission, for administration, or under any obligation to deliver or return it. What matters is that the money was received for a purpose, not lent outright.
What the law says
By misappropriating or converting, to the prejudice of another, money, goods, or any other personal property received by the offender in trust or on commission, or for administration, or under any other obligation involving the duty to make delivery of or to return the same
Revised Penal Code, Article 315 — Swindling (Estafa). Read the full provision →
What this limb of estafa requires
The provision covers misappropriating or converting, to the prejudice of another, money, goods, or any other personal property received by the offender in trust or on commission, or for administration, or under any other obligation involving the duty to make delivery of or to return the same. Four things sit in that sentence: property received under one of those arrangements, a misappropriation or conversion of it, prejudice to the person who gave it, and — implicit in the whole — the duty to deliver or return that the arrangement created.
The line between this and an unpaid debt
This is the distinction the whole question turns on, and it is one of the few places where the law is genuinely counter-intuitive. When money is lent, ownership of it passes to the borrower; he owes an equivalent sum, and failing to pay is a civil matter. When money is handed over for a specific purpose, only possession passes, and the duty is to apply it to that purpose or return it. Article 315 reaches the second situation. So the first question anyone will ask is what the money was handed over for, and on what terms.
Prejudice and the demand that shows refusal
The article requires prejudice to the person who entrusted the property, which is why a case rarely rests on the mere fact that the money is still outstanding. In practice, the way misappropriation is made visible is a demand for return or accounting and what happens next — an unanswered demand, a refusal, an admission that the money went elsewhere. A written demand with proof of receipt is therefore worth far more than repeated conversations, and it also fixes a date from which everything afterwards can be measured.
The evidence that decides it
Find whatever states the purpose: the receipt, the acknowledgment, the chat thread setting out what the money was for, the instruction to buy or remit or hold. That document is what separates a trust arrangement from a loan, and without it the case tends to collapse into a dispute about recollection. Keep the demand and any reply. A note on penalties — the amount brackets in the article were revised by later legislation, so nothing about the applicable penalty should be taken from an older copy of the Code.