A court (RTC Cebu) cannot interfere with property under the custodia legis (custody of the law) of a co-equal court (RTC Makati) by ordering the cancellation and transfer of title of such property; however, a judgment creditor who purchases property subject to a prior attachment at an execution sale has a sufficient legal interest to intervene in the action where the attachment was issued to protect their rights.

Esteban Yau obtained a final judgment against Ricardo Silverio, Sr. from RTC Cebu. The only known asset of Silverio was a proprietary share in Manila Golf and Country Club. This share, however, was already subject to preliminary attachments obtained by Manilabank in separate collection cases against Silverio pending before RTC Makati. This created a conflict when Yau, after purchasing the share at the execution sale ordered by RTC Cebu, sought to have the title transferred to his name.

• Esteban Yau became a judgment creditor of Ricardo C. Silverio, Sr. based on a final and executory decision from RTC Cebu, Branch 6 (Civil Case No. CEB-2058).
• A writ of execution was issued, and the sheriff levied upon Silverio's proprietary membership share in the Manila Golf and Country Club, Inc. (Manila Golf) as Silverio's only known asset.
• On December 29, 1992, Yau purchased the Silverio share for P2 Million at a public auction sale and received a Certificate of Sale.
• Prior to the execution sale, the Silverio share was already subject to writs of preliminary attachment dated March 27, 1990, and October 17, 1990, obtained by Manilabank from RTC Makati, Branches 62 and 64, in separate cases against Silverio (Civil Case Nos. 90-513 and 90-271).
• Yau filed motions to intervene in both Makati cases; Branch 62 denied intervention, while Branch 64 granted it. Manilabank challenged the grant of intervention via certiorari to the CA (CA-G.R. SP No. 32405).
• Yau requested Manila Golf to cancel Silverio's certificate and issue a new one in his name, subject to the attachments; Manila Golf refused due to the notices of garnishment.
• Yau filed a motion in the Cebu case (CEB-2058) seeking an order for Manila Golf to issue the certificate; RTC Cebu granted this motion via Orders dated March 6 and March 30, 1995.
• Manilabank, without filing an MR, filed a certiorari petition with the CA assailing the RTC Cebu orders (CA-G.R. SP No. 37085).
• The CA nullified the RTC Cebu orders in CA-G.R. SP No. 37085, finding interference with a co-equal court (RTC Makati) holding the property in custodia legis. Yau's MR was denied.
• The CA sustained the RTC Makati Branch 64 order allowing Yau's intervention in CA-G.R. SP No. 32405. Manilabank's MR was denied.
• Yau appealed the CA decision in SP No. 37085 to the Supreme Court (G.R. No. 126731).
• Manilabank appealed the CA decision in SP No. 32405 to the Supreme Court (G.R. No. 128623).

• (Yau in G.R. No. 126731) Argued that Manilabank's petition in CA-G.R. SP No. 37085 should have been dismissed for failure to file a motion for reconsideration before RTC Cebu.
• (Yau in G.R. No. 126731) Contended that he was entitled to the issuance of a new certificate after purchasing the share at the execution sale, and RTC Cebu's order did not interfere with RTC Makati's jurisdiction as the new certificate would remain subject to the prior attachments.
• (Manilabank in G.R. No. 128623) Argued that Yau had no legal interest to justify intervention in Civil Case No. 90-271 before RTC Makati, Branch 64, as his rights could be protected separately.
• (Manilabank in G.R. No. 128623) Submitted that Yau's intervention would unduly delay and prejudice the rights of the original parties in the Makati case.
• (Manilabank in G.R. No. 128623) Contended that allowing intervention after trial violates the rule that intervention is only permissible before or during trial.

• (Manilabank in G.R. No. 126731) Argued that the RTC Cebu orders were void as they interfered with the jurisdiction of RTC Makati which held the property under custodia legis via prior attachments.
• (Yau in G.R. No. 128623) Contended that as the purchaser of the attached property at an execution sale, he had a direct legal interest in the subject matter of the Makati litigation and would be adversely affected by its disposition, thus justifying intervention.
• (Yau in G.R. No. 128623) Argued that intervention was necessary to protect his interest before the court having custody of the property (RTC Makati Branch 64).

• Whether the Court of Appeals erred in taking cognizance of Manilabank's certiorari petition (CA-G.R. SP No. 37085) despite the lack of a prior motion for reconsideration filed with RTC Cebu.
• Whether the RTC Cebu City had jurisdiction to order the cancellation of the Silverio share certificate and the issuance of a new one in Yau's name, considering the property was under preliminary attachment by order of RTC Makati City.
• Whether Yau, as the purchaser of the attached property at an execution sale, has the legal interest required to intervene in the main case (Civil Case No. 90-271 before RTC Makati) where the attachment was issued.
• Whether intervention can be allowed after trial has concluded.

• The Supreme Court DENIED both consolidated petitions and AFFIRMED the assailed Decisions of the Court of Appeals.
• The Court held that while a motion for reconsideration is generally required before filing a certiorari petition, an exception exists when the assailed order is a patent nullity, such as when issued by a court without jurisdiction, which was the situation with the RTC Cebu orders.
• The Court ruled that the RTC Cebu lacked jurisdiction to issue orders concerning the Silverio share because the prior notices of garnishment issued by RTC Makati placed the share under the custodia legis of the Makati court. Following the doctrine of judicial stability or non-interference, RTC Cebu, being a co-equal court, could not interfere with property under the control and jurisdiction of RTC Makati.
• The Court found that Yau committed forum shopping by seeking relief from RTC Cebu regarding the share transfer while already allowed to intervene in the RTC Makati case for the same purpose.
• The Court affirmed that Yau possessed the requisite legal interest to intervene in the RTC Makati case (Civil Case No. 90-271), falling under the rule allowing intervention for a person "so situated as to be adversely affected by a distribution or other disposition of property in the custody of the court." As a judgment creditor and purchaser at the execution sale, Yau's rights to the share would be directly affected by the outcome of the Manilabank case.
• Regarding the timing of intervention, the Court noted that the governing rule at the time (Section 2, Rule 12 of the Revised Rules of Court) allowed intervention "before or during trial," and the current rule (Section 1, Rule 19 of the 1997 Rules) allows it "before rendition of judgment by the trial court." Although generally not permitted after trial and decision, the permissive tenor gives the court discretion, and intervention serves to expedite litigation by resolving related matters in one suit. Allowing Yau's intervention before RTC Makati Branch 64 aligns with judicial stability by letting the court with custodia legis resolve claims over the property.

• Custodia Legis: Definition: Property is in the custody of the law when it has been lawfully taken by virtue of legal process. Application: The Silverio share, having been garnished pursuant to writs of preliminary attachment issued by RTC Makati, was under its custodia legis, meaning RTC Makati had exclusive jurisdiction over its disposition, precluding interference by the co-equal RTC Cebu.
• Doctrine of Judicial Stability or Non-Interference: Definition: Courts of equal rank cannot interfere with each other's orders or judgments. Application: RTC Cebu, being co-equal with RTC Makati, violated this doctrine by issuing orders affecting property already under the jurisdiction and control (custodia legis) of RTC Makati Branch 64.
• Intervention: Definition: A procedural mechanism allowing a third person, not originally a party, to join an existing lawsuit because they have a legal interest in the matter under litigation, in the success of either party, or against both, or will be adversely affected by the disposition of property in the court's custody. Application: Yau, as the purchaser at execution sale of the property attached in the Makati case, was deemed to have a sufficient legal interest and would be adversely affected by the disposition of the share, thus justifying his intervention in the Makati case under the then-applicable Rules of Court.
• Forum Shopping: Definition: The act of repetitively availing of several judicial remedies in different courts, simultaneously or successively, involving the same transactions, facts, and issues, seeking the same or substantially the same relief. Application: Yau was found guilty of forum shopping by seeking relief (order for transfer of certificate) from RTC Cebu after already being granted leave to intervene in RTC Makati where he could pursue the same interest regarding the Silverio share.
• Condition Sine Qua Non for Certiorari: Definition: Generally, a motion for reconsideration must be filed with the lower court before a petition for certiorari under Rule 65 can be initiated, to give the lower court an opportunity to correct its alleged error. Application: While Manilabank did not file an MR before RTC Cebu prior to filing its certiorari petition with the CA, the Court held this was excusable as the RTC Cebu orders were deemed a patent nullity due to lack of jurisdiction, fitting a recognized exception to the rule.

• "The garnishment of property operates as an attachment and fastens upon the property a lien by which the property is brought under the jurisdiction of the court issuing the writ. It is brought into custodia legis, under the sole control of such court. A court which has control of such property, exercises exclusive jurisdiction over the same, retains all incidents relative to the conduct of such property. No court, except one having supervisory control or superior jurisdiction in the premises, has a right to interfere with and change that possession."
• "Thus, the doctrine of judicial stability or non-interference in the regular orders or judgments of a co-equal court, as an accepted axiom in adjective law, serves as an insurmountable barrier to the competencia of the RTC Cebu City to entertain a motion, much less issue an order, relative to the Silverio share which is under the custodia legis of RTC Makati City, Branch 64, by virtue of a prior writ of attachment."
• "...[J]urisdiction is vested in the court not in any particular branch or judge, and as a corollary rule, the various branches of the Court of First Instance of a judicial district are a coordinate and co-equal courts one branch stands on the same level as the other. Undue interference by one on the proceedings and processes of another is prohibited by law."
• "It is recognized that a judgment creditor who has reduced his claim to judgment may be allowed to intervene and a purchaser who acquires an interest in property upon which an attachment has been levied may intervene in the underlying action in which the writ of attachment was issued for the purpose of challenging the attachment."

• Parco v. Court of Appeals (111 SCRA 262): Cited to illustrate the policy of peaceful co-existence and non-interference among co-equal courts.
• De Leon v. Salvador (36 SCRA 567): Cited for the principle that property under garnishment is in custodia legis and under the exclusive jurisdiction of the issuing court.
• Tan, Jr. v. Sandiganbayan (292 SCRA 452) / Tan v. Court of Appeals (275 SCRA 568): Referenced for the exceptions to the rule requiring a motion for reconsideration before filing a certiorari petition, specifically the exception where the assailed order is a patent nullity or issued without jurisdiction.
• Ramonito Tantoy, Sr. v. Court of Appeals (G.R. No. 141427): Cited for the definition and elements of forum shopping.
• Trazo v. Manila Pencil Co., Inc. (1 SCRA 403): Cited for the principle that intervention cannot be permitted after a decision has been rendered. (Though the court here allowed intervention based on specific circumstances and rules).
• Mago v. Court of Appeals (303 SCRA 600): Cited regarding the court's discretion in permitting or disallowing intervention.

• Rules of Court, Rule 45: Basis for the petitions for review on certiorari filed with the Supreme Court.
• Rules of Court, Rule 65: Basis for the certiorari petitions filed with the Court of Appeals.
• Revised Rules of Court (prior to 1997), Rule 12, Section 2: Governed intervention at the time of the trial court proceedings; stated intervention may be permitted "before or during trial" for a person with legal interest or who would be adversely affected by disposition of property in custodia legis.
• 1997 Rules of Civil Procedure, Rule 19, Section 1: Current rule on intervention, allowing it "before rendition of judgment by the trial court" under similar conditions of legal interest.
• 1997 Rules of Civil Procedure, Rule 19, Section 2: Referenced implicitly regarding the timing of intervention (current rule states "before rendition of judgment").