1920 Yonge Street, Suite 300
Toronto, ON, M4S 3E2

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Litigation Star



Practice area:

Class action

Sean M. Grayson is a partner at Roy O’Connor LLP. He practices all aspects of corporate/commercial, civil and class actions litigation (both plaintiff and defence) and estate litigation. Sean has diverse experience in matters involving and general corporate and shareholder disputes, arbitrations, director and officer duties, responsibilities and indemnities, securities litigation – OSC/IIROC and secondary market liability matters, estate matters, mining disputes, negligence and contractual disputes, matters involving financial institutions, investment advisor disputes, employment disputes, matters before regulated health profession boards, and executive compensation. In recent years Sean has been recognized by Benchmark Canada as a Litigation Star. 

Some of the recent and ongoing matters Sean is currently involved in include: 

  • Acting as counsel for various defendant franchisees in an employment class action 
  • Acting as counsel for an officer and director in respect of various misrepresentation claims by shareholders against a former public company 
  • Successfully acting for a mutual fund dealer and other entities in the defence of a class proceeding in respect of various allegations and claims, including breach of fiduciary duty 
  • Successfully acting as counsel for an executive officer, and part of a counsel team in a secondary market class proceeding 
  • Acting for a royalty holder in respect of a surface rights mining claim dispute 
  • Successfully acting on behalf of a group of beneficiaries in a trust/oppression application in respect of multiple estate freezes and trusts in a multitude of proceedings 
  • Successfully acting for an estate trustee in respect of among other things, a will challenge 
  • Successfully acting on behalf of a company in a lengthy contested shareholder arbitration 
  • Acting on behalf of a purchaser in an arbitration involving alleged misrepresentations in financial statements 
  • Acting as counsel for a public company in respect of claims by an investor related to its listing 
  • Acting on behalf of a seller in an arbitration involving alleged financial statement misstatement, fraud and negligence 
  • Acting on behalf of private company to remove a cease trade order of the OSC for non-compliance with NI 43-101, and ongoing negligence claims flowing from the CTO and damage to the company; 
  • Acting for a private company and individual benefices and shareholders in a will challenge and related oppression claim 
  • Acting as litigation counsel in various plans of arrangement 
  • Acting as part of counsel group with other members of the firm in various class actions including Quenneville et al. v. Volkswagen et al. (Volkswagen Diesel Emission Manipulations), acting as part of the counsel team for a group of independent directors in Gould v. Western Coal et al., a class and secondary market liability action. Successfully acting as part of the counsel team in the national class proceeding in respect of the constitutional challenge of survivor pension benefits, Hislop v. Canada, acting as part of the counsel team for the pre-1986 and post-1990 Hepatitis C settlement against the Federal Government, acting on behalf of a group of condominium purchasers in a class proceeding brought for alleged overcharges for development fees, part of the counsel team in several national unpaid overtime class actions with respect to alleged unpaid overtime and misclassification of employees, the defence of various class proceedings and other proceedings arising out of the collapse of Bre-X Minerals, among others.

Updated April 2023