The Ontario Superior Court of Justice has set aside a previous court order that had allowed the Toronto Regional Real Estate Board, known as TRREB, to amend its lawsuit and add a personal defendant to an ongoing data misuse case1. In a decision released on December 23, 2025, Justice Cavanagh ruled that TRREB failed to make full and fair disclosure of material facts when it originally sought permission to amend its claim without notifying the opposing party. The ruling highlights the strict procedural obligations placed on plaintiffs when they seek court orders without the presence of the defendants.
The dispute centers on allegations regarding the unauthorized access and use of the TRREB Multiple Listing Service, or MLS System. On February 14, 2025, TRREB initiated an action against IMS Incorporated, which operates under the names RESTATS and Reality. TRREB sought declaratory relief, damages, and an injunction to stop IMS from accessing and copying the contents of the MLS System. The allegations in the lawsuit included breach of confidence, breach of privacy, and interference with economic relations. However, TRREB did not immediately serve this Statement of Claim on IMS after it was issued.
Months later, on July 15, 2025, TRREB went before the court to request permission to amend its Statement of Claim. The proposed amendments were significant. TRREB sought to add new causes of action against IMS and, crucially, requested to add Leon D’Ancona as a personal defendant. D’Ancona is an officer and director of IMS. The new claims alleged breach of contract and inducing breach of contract against both the company and D’Ancona personally. TRREB brought this motion on an ex parte basis, meaning they appeared before the judge without giving notice to IMS or D’Ancona.
At that July hearing, TRREB argued that serving notice of the motion was unnecessary because the original Statement of Claim had not yet been served on the defendants. Relying on the rules of civil procedure, TRREB suggested that the court could make the order without notice. Justice Dietrich, who heard the motion in July, granted the request. She issued an order giving TRREB leave to amend the pleading and add D’Ancona to the lawsuit. Following this success, TRREB served the Fresh as Amended Statement of Claim on the defendants in August 2025.
The litigation took a turn in September 2025 when the defendants, IMS and D’Ancona, filed a motion to set aside Justice Dietrich’s order. They argued that TRREB had not played by the rules required for ex parte motions. Specifically, the defendants contended that TRREB failed to disclose the existence and procedural history of a separate lawsuit involving the same parties in the Federal Court. The defendants argued that this omission constituted a failure to make full and fair disclosure of all material facts, which is a requirement when a party seeks relief from the court without the other side present to argue their case.
The history of the Federal Court action dates back to August 10, 2020. At that time, TRREB filed a statement of claim in Federal Court against both IMS and D’Ancona. That lawsuit involved claims for copyright breaches associated with the use of the MLS Service, as well as claims for breach of privacy and proprietary rights. During the Federal Court proceedings, the defendants brought a motion to strike the claim. A Case Management Judge struck out several claims, including the allegations against D’Ancona personally. The judge in the Federal Court matter ruled that TRREB had failed to plead conduct that would attract personal liability for a corporate officer, noting there was nothing in that claim alleging D’Ancona acted outside the scope of his role as a director.
While TRREB eventually appealed portions of that Federal Court decision regarding copyright claims, the history of the attempt to sue D’Ancona personally in 2020 became the focal point of the current Ontario dispute. The defendants in the Ontario action argued that if Justice Dietrich had been told about the 2020 Federal Court filing and the subsequent striking of claims against D’Ancona, it would have impacted her decision. They submitted that this history was relevant to the issue of limitation periods. In Ontario, there is generally a two-year limitation period to start a lawsuit after a claim is discovered. The defendants argued that the 2020 lawsuit proved TRREB was aware of potential claims against D’Ancona more than two years before trying to add him to the Ontario lawsuit in 2025.
Justice Cavanagh reviewed the legal principles governing motions to amend pleadings and the specific requirements for motions brought without notice. The court noted that on a motion to add a party, the court must consider whether the proposed amendments are legally tenable and whether they would result in prejudice that cannot be compensated by costs. A key factor in determining prejudice is whether a limitation period has expired, which would bar the addition of a new party to an existing action.
The court emphasized the heavy burden on a moving party to make complete disclosure when proceeding ex parte. Because the opposing party is not there to present evidence or challenge the facts, the moving party must ensure the information before the court is complete, true, and plain. Material facts are defined as those that might affect the court’s decision or the outcome of the motion. The failure to disclose such facts is, in itself, sufficient ground for setting aside an order obtained on the motion.
TRREB defended its actions by arguing that the existence of the Federal Court action was disclosed in the materials before Justice Dietrich, as it was referenced in the pleadings. TRREB also argued that they only discovered the specific methods D’Ancona used to access the system, such as personal representations to brokerages and specific agreements signed in 2024 and 2025, after the Ontario claim was issued. They contended that because some of the alleged breaches occurred recently, no limitation period could have expired regarding those specific 2024 and 2025 agreements.
Justice Cavanagh rejected TRREB’s position. He found that the references to the Federal Court action in the materials provided to Justice Dietrich were insufficient. The materials did not disclose that a claim had been made against D’Ancona in that action for wrongfully accessing the system, nor did they disclose that the claim had been struck out. The Justice noted that TRREB’s pleadings in the Ontario action only referred to a claim in the Federal Court against IMS for copyright breaches, which did not paint the full picture of the prior litigation against D’Ancona.
The court found that the history of the Federal Court action was indeed material. If the motions judge in July had known that TRREB attempted to sue D’Ancona for similar conduct in 2020, she might have questioned whether the limitation period had expired for the claims in the current lawsuit. This information would have been relevant to determining whether the amendment would cause non-compensable prejudice to the defendants. Justice Cavanagh reasoned that with full knowledge of the Federal Court history, Justice Dietrich might have decided that notice to the defendants was necessary rather than optional, or she might have adjourned the motion to allow the defendants to be served.
Justice Cavanagh also addressed TRREB’s argument regarding the timing of discovery. TRREB asserted that the limitations issue should be left for a trial judge to decide and that the amendments were based on newly discovered facts. However, the court pointed out that because the full history was not disclosed, the judge in July was unable to properly assess the defendants’ potential position that TRREB had discovered its claims years prior. Determining when a plaintiff discovered a claim is a matter of evidence, and by proceeding without notice and without full disclosure, TRREB deprived the court of the ability to consider the counter-arguments regarding the timeline of events.
The court concluded that TRREB failed to make full and fair disclosure of all material facts as required by rule 39.01(6) of the Rules of Civil Procedure. TRREB urged the court to exercise its discretion and not set aside the order, arguing that doing so would increase costs and waste court time, as they would simply bring the motion again. They also argued that because the Statement of Claim hadn’t been served initially, there was no procedural unfairness.
Justice Cavanagh disagreed with these submissions. He stated that the motion to amend the pleading affected both IMS and D’Ancona, regardless of whether they had been served with the original claim. Consequently, notice should have been provided unless the rules explicitly allowed otherwise. The court saw no reason why the motion was not brought on notice to the parties who would be affected by the order. The Justice emphasized that by choosing to move without notice, TRREB accepted the obligation of full disclosure and the risk that the order could be set aside if they failed to meet that obligation.
The court adhered to the general rule that an order obtained without full and fair disclosure will be set aside. Justice Cavanagh granted the defendants’ motion and set aside the order dated July 15, 2025. This decision effectively returns the parties to the position they were in before the amendment was granted, requiring TRREB to restart the process of seeking leave to amend its claim if it wishes to pursue the additional allegations and the addition of D’Ancona as a defendant. The court left the issue of costs to be determined through written submissions if the parties cannot reach an agreement. The underlying merits of the data misuse allegations remain to be adjudicated in the ongoing litigation.
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