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Case information

Conduct a refined search of the Supreme Court of Canada database to obtain details on the status of a matter before the Court.


41990

John Sherlock v. Katherine Ann Mullin

(Ontario) (Civil) (By Leave)

Docket

Judgments on applications for leave to appeal are rendered by the Court, but are not necessarily unanimous.

List of proceedings
Date Proceeding Filed By
(if applicable)
2026-04-10 Close file on Leave
2026-04-09 Copy of formal judgment sent to Registrar of the Court of Appeal and all parties
2026-04-09 Judgment on leave sent to the parties
2026-04-09 Judgment of the Court on the application for leave to appeal, The motion for an extension of time to serve and file the response is granted. The application for leave to appeal from the judgment of the Court of Appeal for Ontario, Number COA-23-CV-0787, 2025 ONCA 510, dated July 15, 2025, is dismissed with costs.
Dismissed, with costs
2026-04-09 Decision on motion to extend time, See decision on application., CJ Row Ob
2026-03-09 All materials on application for leave submitted to the Judges, for consideration by the Court
2026-03-09 Submission of motion to extend time, CJ Row Ob
2026-02-20 Correspondence received from, (Letter Form), the applicant- will not be filing a reply , (Printed version due on 2026-02-27) John Sherlock
2026-02-13 Certificate (on limitations to public access), (Letter Form), 23A, (Printed version filed on 2026-02-13) Katherine Ann Mullin
2026-02-13 Motion to extend time, (Book Form), (Included in the respondent's response on the application for leave to appeal), Completed on: 2026-02-13, (Printed version filed on 2026-02-13) Katherine Ann Mullin
2026-02-13 Respondent's response on the application for leave to appeal, (Book Form), Completed on: 2026-02-13, (Printed version filed on 2026-02-13) Katherine Ann Mullin
2026-01-30 Correspondence received from, the respondent requested further extension of time for service and filing a response by February 13, 2026. Katherine Ann Mullin
2025-10-24 Lower court order - e-filing, (Letter Form), CA Orders, (Printed version filed on 2025-10-28) John Sherlock
2025-10-17 Correspondence received from, (Letter Form), the respondent for an extension of time for service and filing a response by January 31, 2026., (Printed version due on 2025-10-24) Katherine Ann Mullin
2025-10-07 Correspondence received from, (Letter Form), (Printed version filed on 2025-10-17) John Sherlock
2025-09-22 Letter acknowledging receipt of an incomplete application for leave to appeal and without formal Court of Appeal order, FILE OPENED
2025-09-19 Certificate (on limitations to public access), (Letter Form), 23A, (Printed version filed on 2025-09-22) John Sherlock
2025-09-19 Application for leave to appeal, (Book Form), Missing
CA Orders (Rec'd 2025-10-24), Completed on: 2025-10-24, (Printed version filed on 2025-09-22)
John Sherlock

Parties

Please note that in the case of closed files, the “Status” column reflects the status of the parties at the time of the proceedings. For more information about the proceedings and about the dates when the file was open, please consult the docket of the case in question.

Main parties

Main parties - Appellants
Name Role Status
Sherlock, John Applicant Active

v.

Main parties - Respondents
Name Role Status
Mullin, Katherine Ann Respondent Active

Counsel

Party: Sherlock, John

Counsel
Names
Jonathan Robinson
Heather Hansen
Maura O'Sullivan
Contact information
McCarthy Hansen & Company LLP
1133 Yonge Street
Suite 601
Toronto, Ontario
M4T 2Y7
Telephone: (416) 862-6226
FAX: (416) 862-9001
Email: jonathan@mccarthyco.ca
Agent
Name
Catherine Ouellet
Contact information
Gowling WLG (Canada) LLP
160 Elgin Street
Suite 2600
Ottawa, Ontario
K1A 5C6
Telephone: (613) 786-0189
FAX: (613) 563-9869
Email: Catherine.Ouellet@gowlingwlg.com

Party: Mullin, Katherine Ann

Counsel
Names
Robert M. Halpern
Jessica Brown
Contact information
Halpern Law Group
45 St Clair Avenue West
Suite 702
Toronto, Ontario
M4V 1K6
Telephone: (416) 792-3399 Ext: 201
Email: rhalpern@halpernlawgroup.ca
Agent
Name
David R. Elliott
Contact information
Dentons Canada LLP
99 Bank Street
Suite 1420
Ottawa, Ontario
K1P 1H4
Telephone: (613) 783-9699
FAX: (613) 783-9690
Email: david.elliott@dentons.com

Summary

Keywords

Family law — Divorce — Family assets — Support — Unjust enrichment — Wife receiving monetary damages based on unjust enrichment arising out of joint family venture and lump sum payment of spousal support from lower courts — To what extent, and in what circumstances, should courts be able to employ unjust enrichment to engage in a de facto equalization process beyond that fixed by provincial legislation regarding division and/or equalization of matrimonial property — Family Law Act, R.S.O. 1990, c. F.3.

Summary

Case summaries are prepared by the Office of the Registrar of the Supreme Court of Canada (Law Branch). Please note that summaries are not provided to the Judges of the Court. They are placed on the Court file and website for information purposes only.

The parties began living together in 2000 and were married in 2012 after living together for nearly twelve and a half years. They were separated in 2013 after almost 10 months of marriage. At trial, the wife sought $3,000,000 in monetary damages based on unjust enrichment arising out of a joint family venture, a lump sum payment of spousal support consisting of both retroactive and prospective payments, and prejudgment interest. The trial judge awarded her $3,000,000 in monetary damages and $365,624 as lump sum spousal support and costs.

The husband appealed and the Court of Appeal dismissed the appeal.

Lower court rulings

June 22, 2023
Ontario Superior Court of Justice

2023 ONSC 3744

Ms. Mullin awarded $3,000,000 in monetary damages and $365,624 as lump sum spousal support and costs.


July 15, 2025
Court of Appeal for Ontario

2025 ONCA 510

Appeal dismissed.

Filed documents

The memorandums of argument on an application for leave to appeal will be posted here 30 days after leave to appeal has been granted unless they contain personal information, information that is subject to a publication ban, or any other information that is not part of the public record. You may also obtain copies of the memorandum by filling out the Request for Court records form or by contacting the Court’s Records Centre either by email at records-dossiers@scc-csc.ca or by telephone at 613‑996‑7933 or at 1‑888‑551‑1185.

If you have questions about a memorandum of argument or want to use a memorandum of argument, please contact the author of the memorandum of argument directly. Their name appears at the end of the memorandum of argument. The contact information for counsel is found in the “Counsel” tab of this page.

Downloadable PDFs

Not available

The factums of the appellant, the respondent and the intervener will be posted here at least 2 weeks before the hearing unless they contain personal information, information that is subject to a publication ban, or any other information that is not part of the public record. You may also obtain copies of factums by filling out the Request for Court records form or by contacting the Court’s Records Centre either by email at records-dossiers@scc-csc.ca or by telephone at 613‑996‑7933 or at 1‑888‑551‑1185.

If you have questions about a factum or want permission to use a factum, please contact the author of the factum directly. Their contact information appears on the first page of each factum.

Downloadable PDFs

Not available

The condensed books of the appellant, the respondent and the intervener will be posted here upon receipt of the electronic version, 2 days prior to the scheduled appeal hearing. You may also obtain copies of condensed books by filling out the Request for Court records form or by contacting the Court’s Records Centre either by email at records-dossiers@scc-csc.ca or by telephone at 613‑996‑7933 or at 1‑888‑551‑1185.

If you have questions about a condensed book or want permission to use a condensed book, please contact the author of the condensed book directly. Their contact information appears on the first page of each condensed book.

Downloadable PDFs

Not available

Webcasts

Not available.

Date modified: 2026-04-11