Short answer. File a third-party claim, known as a terceria: serve on the levying officer an affidavit of your title or right to possession, stating its grounds, with a copy to the judgment creditor. The sheriff is not bound to keep the property unless the creditor files a court-approved indemnity bond of at least its value; you may also sue separately.
What the law says
makes an affidavit of his title thereto or right to the possession thereof, stating the grounds of such right or title, and serves the same upon the officer making the levy and a copy thereof upon the judgment obligee
Rule 39, Section 16 — Proceedings where property claimed by third person. Read the full provision →
What the law says
Nothing herein contained shall prevent such claimant or any third person from vindicating his claim to the property in a separate action
Rule 39, Section 16 — Proceedings where property claimed by third person. Read the full provision →
The affidavit that takes the sheriff out of it
Rule 39, Section 16 exists precisely for your situation: the levy caught property belonging to someone other than the judgment debtor. The remedy starts with a sworn claim — the third-party claimant makes an affidavit of his title thereto or right to the possession thereof, stating the grounds of such right or title, and serves the same upon the officer making the levy and a copy thereof upon the judgment obligee. Once that affidavit is served, the officer shall not be bound to keep the property. The pressure shifts to the winning creditor: keep the levy alive, or let the property go.
The creditor's counter: an indemnity bond
The creditor can hold the levy only by filing a bond, approved by the court, to indemnify you in a sum not less than the value of the property levied on — and if you and the creditor disagree on that value, the court that issued the writ of execution determines it. The bond is your protection, but it comes with a clock: no claim for damages for the taking or keeping of the property can be enforced against the bond unless the action is filed within one hundred twenty days from the date the bond was filed. Once the bond is in place, the officer himself is no longer liable to you for the taking or keeping.
The terceria is not your only road
The summary claim inside the execution proceedings does not exhaust your remedies: Nothing herein contained shall prevent such claimant or any third person from vindicating his claim to the property in a separate action. So even if the creditor posts the bond and the sale pushes through, you can still sue independently to establish your ownership. The street runs both ways, though — the rule also lets the judgment creditor claim damages, in the same or a separate action, against a third-party claimant whose claim was frivolous or plainly spurious. The affidavit is a sworn statement; make it only on grounds you can prove.
Move quickly, and paper the claim properly
Serve the affidavit before the property is sold at auction — after that, the fight becomes harder and different. Attach the proof of your right to the grounds you state: the title or deed in your name, receipts, the document showing you acquired the property before the levy. One caveat from the rule itself: when the writ of execution is issued in favour of the Republic of the Philippines, no indemnity bond is required of it, so the mechanics differ where the government is the winning party. A lawyer will want the sheriff's levy documents and your ownership papers side by side.