A party is barred by estoppel by laches from questioning a court's jurisdiction over the subject matter if they actively participated in all stages of the case before the lower court and only raised the jurisdictional challenge belatedly after an unfavorable judgment, especially after a significant lapse of time.

The case originated from a loan obtained by Relia Arciga from Jaycee P. Baluyut, secured by a Real Estate Mortgage (REM) over a property co-owned by Relia and her mother, Rita Quizon-Arciga. The authority to mortgage was derived from an Extra-Judicial Settlement of Estate/Partition with Special Power of Attorney (EJS-SPA). Upon default, Baluyut initiated judicial foreclosure proceedings.

• On December 5, 2002, petitioners Rita Quizon-Arciga and Relia Q. Arciga executed a Deed of Extra-Judicial Settlement of Estate/Partition with Special Power of Attorney (EJS-SPA) over a property in Concepcion, Tarlac, covered by TCT No. 142572, leading to the issuance of TCT No. 395377 in their names.
• On August 11, 2005, Relia Arciga obtained a loan of P500,000.00 from respondent Jaycee P. Baluyut, with an interest rate of 8% per month, payable after 5 months.
• Relia, using the EJS-SPA, executed a Real Estate Mortgage (REM) over the property in favor of Baluyut to secure the loan.
• Relia failed to pay the obligation upon maturity despite repeated demands.
• On June 26, 2008, Baluyut filed a complaint for judicial foreclosure of mortgage against the petitioners. The complaint did not allege the assessed value of the subject property.
• Petitioners, in their Answer, argued that Relia lacked authority to mortgage Rita's share as the EJS-SPA allegedly authorized mortgaging only to an "Amelia G. Pineda."
• The RTC ruled in favor of Baluyut, ordering petitioners to pay the loan with 8% monthly interest. Petitioners manifested they would not appeal and intended to settle.
• The property was sold at public auction to Baluyut, the sale was confirmed, and a Writ of Possession was issued and implemented.
• Five months after Baluyut took possession, petitioners filed an Omnibus Motion to nullify the sale, arguing the 8% monthly interest was unconscionable; the RTC denied this.
• Petitioners then filed a Petition for Annulment of Judgment with the CA, reiterating the argument about the unconscionable interest rate.
• In their Motion for Reconsideration before the CA, petitioners newly argued extrinsic fraud due to their counsel's gross negligence and lack of RTC jurisdiction because the complaint failed to state the property's assessed value and pay correct docket fees.

• The RTC had no jurisdiction to order the payment of the 8% monthly interest on the P500,000.00 loan because such interest is excessive, exorbitant, unconscionable, and contrary to morals and public policy, rendering the RTC decision void.
• The gross negligence of their previous counsel in handling their case constitutes extrinsic fraud, a ground for annulment of judgment.
• Respondent's failure to indicate the assessed and market value of the property in the judicial foreclosure complaint and to pay the corresponding correct docket fees prevented the RTC from acquiring jurisdiction over the subject matter.
• The issue of jurisdiction can be raised at any time, even on appeal.

• Petitioners' assertions of their counsel's gross negligence and failure to pay correct docket fees should not be considered as they were belatedly raised only in their motion for reconsideration before the CA.
• The RTC's decision became final and executory because petitioners voluntarily decided not to appeal it, not due to any extrinsic fraud.
• Petitioners are estopped from questioning the RTC's jurisdiction after actively participating in the proceedings and only raising the issue after losing the case and after many years.

• Whether the Court of Appeals correctly dismissed the petitioners' petition for annulment of judgment.
• Whether extrinsic fraud existed due to the alleged gross negligence of petitioners' counsel.
• Whether the RTC lacked jurisdiction over the subject matter due to the failure to allege the assessed value of the property in the complaint.
• Whether petitioners are estopped by laches from questioning the RTC's jurisdiction.

• The Petition for Review on Certiorari is DENIED. The Resolutions of the Court of Appeals are AFFIRMED.
• The Court found no extrinsic fraud. To constitute extrinsic fraud, the fraudulent scheme must have been devised by the prevailing litigant (respondent). Here, the alleged gross negligence was attributed to petitioners' own counsel, not the respondent. Furthermore, records show petitioners themselves decided not to appeal the RTC's decision to settle the civil aspect of the case.
• The Court agreed that the RTC initially had no jurisdiction. A complaint for foreclosure of REM is a real action, and jurisdiction depends on the assessed value of the property. The respondent's complaint failed to allege this assessed value, making it impossible to determine if the RTC or the Municipal Trial Court had jurisdiction.
• However, the Court ruled that petitioners are estopped by laches from questioning the RTC's jurisdiction. They actively participated in all stages of the RTC proceedings, presented witnesses, and only raised the jurisdictional issue for the first time in their motion for reconsideration before the CA, twelve years after the complaint was filed. This belated challenge, after voluntarily submitting to the RTC's jurisdiction and obtaining an unfavorable judgment, bars them from repudiating the RTC's decision.

• Annulment of Judgment (Rule 47, Rules of Court) — A remedy in equity available only when ordinary remedies (new trial, appeal, petition for relief) are no longer available through no fault of the petitioner, and based only on extrinsic fraud or lack of jurisdiction. It was invoked by petitioners to nullify the RTC decision but was ultimately denied.
• Extrinsic Fraud — Fraud which prevents a party from having a trial, or real contest, or from presenting all of his case to the court, or where it operates upon matters not pertaining to the judgment itself, but to the manner in which it was procured. The Court ruled that the alleged gross negligence of petitioners' own counsel does not constitute extrinsic fraud attributable to the respondent, which is required for annulment of judgment.
• Jurisdiction over Real Actions (Batas Pambansa Blg. 129, as amended by Republic Act No. 7691) — For real actions, jurisdiction is determined by the assessed value of the property. RTCs have exclusive original jurisdiction if the assessed value exceeds P20,000.00 (or P50,000.00 in Metro Manila), otherwise, it is with the first-level courts. The Court found that the complaint's failure to allege the assessed value meant the RTC's jurisdiction was not properly established.
• Estoppel by Laches (Doctrine of Tijam v. Sibonghanoy) — A party may be barred by laches from invoking lack of jurisdiction if they actively participated in the trial and only raised the jurisdictional issue after an unfavorable decision and after an unreasonable length of time. The Court applied this doctrine to bar petitioners from questioning the RTC's jurisdiction, as they participated for twelve years before raising the issue.
• Determination of Jurisdiction from Complaint Allegations — Jurisdiction over the subject matter is determined by the allegations in the complaint and the character of the relief sought. The Court noted that the complaint lacked the necessary allegation of assessed value to determine jurisdiction.

• "To constitute extrinsic fraud, the scheme which prevented a party from having his or her day in court must have been devised by the prevailing litigant."
• "Estoppel sets in when 'a party participates in all stages of a case before challenging the jurisdiction of the lower court. One cannot belatedly reject or repudiate its decision after voluntarily submitting to its jurisdiction, just to secure affirmative relief against one's opponent or after failing to obtain such relief.'"
• "Verily, it is already too late for petitioners to challenge the RTC's jurisdiction on the ground that the complaint failed to allege the assessed value of the subject property. For participating in all stages of the case before the lower court, petitioners are indubitably barred by estoppel from challenging the lower court's jurisdiction."

• Lagundi v. Bautista — Cited as precedent for applying estoppel by laches to bar a party from invoking lack of jurisdiction when the issue (failure to allege assessed value) was raised very late in the proceedings after active participation. The current case was found similar to Lagundi.
• Tijam v. Sibonghanoy — The landmark case establishing the doctrine of estoppel by laches in relation to jurisdictional challenges. Reiterated in Lagundi and applied here.
• Cosmic Lumber Corp. v. Court of Appeals — Cited for the definition of extrinsic fraud.
• Teodoro v. Court of Appeals — Cited for the principle that extrinsic fraud must be committed by the prevailing party.
• Pinausukan Seafood House, Roxas Blvd., Inc. v. Far East Bank & Trust Co. — Cited in relation to extrinsic fraud not being attributable to one's own counsel's negligence for purposes of annulment of judgment.
• Roldan v. Sps. Barrios — Cited to establish that foreclosure of REM is a real action and jurisdiction depends on the assessed value of the property.
• Fort Bonifacio Development Corporation v. Domingo — Cited for the rule that jurisdiction is determined by the allegations in the complaint.
• Spouses Cruz v. Spouses Cruz — Cited for the principle that only facts alleged in the complaint form the basis for determining the nature of the action and jurisdiction.
• Quinagoran v. Court of Appeals — Cited for the rule that courts are not authorized to take judicial notice of the assessed value of land.
• Bernardo v. Heirs of Eusebio Villegas — Cited for the definition of when estoppel sets in regarding jurisdictional challenges.

• Rule 47, Section 1, Rules of Court — Governs actions for annulment of judgments, specifying it is available when ordinary remedies are lost without the party's fault. The Court found petitioners did not meet this condition.
• Rule 47, Section 2, Rules of Court — States the only grounds for annulment of judgment: extrinsic fraud and lack of jurisdiction. Both grounds were invoked by petitioners but ultimately rejected by the Court.
• Batas Pambansa Blg. 129, Section 19(2) — Defines the jurisdiction of Regional Trial Courts in civil cases involving title to, or possession of, real property, based on assessed value. The Court noted the complaint's deficiency under this provision.
• Batas Pambansa Blg. 129, Section 33(3) — Defines the jurisdiction of Metropolitan Trial Courts, Municipal Trial Courts, and Municipal Circuit Trial Courts over real property based on assessed value. This section, in conjunction with Sec. 19(2), determines which court has jurisdiction.