Skip to content.
This is a photo of William Main




Contact by email at [email protected]

t. +1 416-601-8235


Will develops and executes strategies to advance his clients’ interests and deliver solutions tailored to his clients’ priorities. Will utilizes a diverse set of litigation and other tools to attain results.

Will continues to grow a broad litigation and advisory practice centered around complex and high stakes commercial litigation. Will has acted for clients on matters involving commercial disputes, class actions, securities litigation, shareholder disputes, M&A litigation, regulatory and enforcement proceedings, privacy litigation, defamation, political law, and professional negligence. Will also assists clients with conducting sensitive internal investigations, and advises clients in the commercial, corporate, and privacy spaces.

Will’s clients come from across the private and public sphere in Canada, including from the banking and finance, technology, manufacturing, consumer goods, and mining sectors. Will’s clients include financial institutions, asset managers and investment firms, public issuers, tech companies, mining companies, high-profile political figures, municipalities, media entities, and professionals.

Will has represented clients before the Ontario Court of Appeal, Ontario Superior Court of Justice, Federal Court, Ontario Securities Commission, Alberta Securities Commission, Information and Privacy Commissioner of Ontario, Health Professions Appeal and Review Board, and Discipline Committee of the College of Physicians and Surgeons of Ontario. Will has also acted as counsel in private commercial arbitration and mediation proceedings.


Some of Will’s recent notable mandates include:

Corporate & Commercial Litigation

  • Representing an asset management firm in an arbitration and mediation relating to a joint venture shareholder dispute. After defeating two motions brought by the opposing party, a resolution to the dispute was successfully negotiated.
  • Representing an AI company in litigation alleging economically damaging and tortious conduct against a competitor. A resolution to the dispute was successfully negotiated.
  • Representing a software technology company in a dispute over work performed for and fees owed by a corporate client. A resolution to the dispute was successfully and quickly negotiated.
  • Counsel to an EV company in respect of a dispute over advertising with an Ontario motor vehicle regulator. The EV company prevailed at a hearing of the dispute.
  • Representing a major Canadian federation of credit unions in respect of an alleged fraud incident at the expense of the company. A resolution was successfully and quickly negotiated, the company receiving reimbursement for the losses it had suffered.
  • Counsel to a defendant brewing company in a proposed class action against the LCBO and several major players in the Ontario beer market (the “Beer Store Class Action”), which was successfully dismissed by pre-certification summary judgment (Hughes v. Liquor Control Board of Ontario2018 ONSC 1723, upheld on appeal Hughes v. Liquor Control Board of Ontario2019 ONCA 305).
  • Counsel to the successful financial institution in Jama v. National Bank2017 ONSC 1424, which was dismissed by summary judgment.
  • Counsel to a major Canadian technology and consulting company in a multi-million dollar private arbitration relating to a significant government project.


  • Counsel to a major international mining company in respect of a contested takeover and related litigation.
  • Internal investigation with potential securities law implications for a Canadian financial services company.
  • Representing a global asset management company based in Canada in a dispute before the Alberta Securities Commission relating to a takeover.
  • Counsel to a major Canadian cannabis company in respect of regulatory compliance issues with potential securities implications. Conducted an internal investigation, advised the Special Committee of the Board, dealt with regulators, defended class and other litigation.
  • Internal investigation with potential securities law implications for a Canadian biotechnology company.
  • Internal investigation with potential securities law implications for a major Canadian raw materials manufacturing company.
  • Counsel to the respondent in Caldwell Investment Management Ltd. (Re)2019 ONSEC 25, the first enforcement proceeding in Canada relating to best execution.

Communications, Technology, and Privacy

  • Representing Meta in Canada (Privacy Commissioner) v. Facebook, Inc., 2023 FC 533, an application brought by the Privacy Commissioner under PIPEDA.
  • Counsel to a Canadian technology company in respect of a commercial dispute and alleged cyber incidents.
  • Confidential advice regarding cyber and data breaches.
  • Representing CBC in Subway v. CBC, responding to a $210 million defamation case brought by Subway with respect to a Marketplace  episode concerning chicken products at quick service restaurants.
  • Representing a Canadian engineering sales company in a defamation action against a California technology company. Representation included successfully defeating an anti-SLAPP motion brought by the defendant (Echelon v. Glassdoor2021 ONSC 5701, under appeal), an appeal of same (Echelon Environmental Inc. v. Glassdoor Inc., 2022 ONCA 391), and a motion to extend time to seek leave to appeal brought by a third party (Echelon Environmental Inc. v. Glassdoor Inc.2021 ONCA 763).
  • Representing CBC in opposing a publication ban sought by a defendant in a criminal proceeding.
  • Representing Desjardins General Insurance Group Inc. and one of its employees in Wakeling v. Desjardins, a claim alleging the privacy tort of intrusion upon seclusion, among other claims. The breach of privacy and other claims were struck out with costs and without leave to amend (Wakeling v. Desjardins General Insurance Group Inc.2020 ONSC 6809). The decision was upheld on appeal, with costs (Wakeling v. Desjardins General Insurance2021 ONCA 672).
  • Advising and representing clients in respect of advancing or responding to access to information requests, for clients including:
  • Two Canadian retail companies;
  • A Canadian food company; and
  • A Chinese technology company.
  • Counsel to a then-Federal Cabinet Minister responding to an application by a member of the public to compel that the Minister unblock them on a social media platform, on Charter and other grounds.
  • Counsel to a prominent former politician responding successfully to an inquiry by the Federal Ethics Commissioner.
  • Representing a media company in challenging a production order in the context of a criminal investigation.
  • Advising and advocating for a significant Canadian company in respect of a series of Access to Information Requests at a sensitive legal and commercial time for the company.
  • Defending a physician in a defamation action brought in respect of a consultation report he authored.
  • Representing a physician in respect of a complaint made to the Information and Privacy Commissioner of Ontario.
  • Providing privacy law compliance advice in respect of a significant hospital construction project.
  • Advising a municipality regarding sensitive defamation matters with a political dimension.
  • Representing a Canadian food manufacturing company in respect of a debt dispute with defamation claim by counter-claim.
  • While still a student at McCarthy’s, assisting with a 13-week jury trial on behalf of CBC and three of its journalists. The action had been brought by a former academic, Ranjit Chandra, seeking $132 million in damages for defamation and breach of privacy arising out of a three-part documentary program broadcast on The National. The claim was dismissed in its entirety at trial, the jury having accepted CBC’s truth defence. CBC was awarded more than $1.6 million in costs (Chandra v. CBC2015 ONSC 6519). Dr. Chandra’s motion for an extension of time to seek leave to appeal was dismissed (Chandra v. Canadian Broadcasting Corporation2016 ONCA 448).

Professional Negligence

  • Counsel on a large group claim for negligence against an insurance brokerage.
  • Defending medical negligence claims and payment demands on behalf of the CMPA, physicians, their clinics, and clinic staff.
  • Regulatory and other advice to physicians and companies in the health and wellness sector.
  • Counsel to the successful respondent physician on an appeal to the HPARB in  v. P. J. R. S., 2020 CanLII 12632(ON HPARB).
  • Counsel to the successful respondent physician on an appeal to the HPARB in Applicant v. G.B.J.2017 CanLII 53783(ON HPARB).

Will is an Adjunct Moot Advisor of the University of Toronto Law School's Corporate Securities Competitive Program, and a Guest Lecturer at the University of Western Ontario Faculty of Law Advanced Securities course. Will authored a chapter on Privacy in the recent LexisNexis textbook Virtual Advocacy: Litigating from a Distance.

Will is a proud member of the Board of SPRINT Senior Care, and a volunteer Will also volunteers with Pro Bono Ontario. He is a member of the Canadian Bar Association, the Ontario Bar Association, and the Advocates’ Society.