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Louise R. Summerhill

Partner* Admitted to the Ontario Bar: 1990
*Practising as a professional corporation

A creative thinker and natural problem solver, Louise continuously looks for new ways to approach and resolve her clients’ tax issues. Her technical expertise and knowledge of her clients’ businesses leads to solutions others may not see. When she takes matters to court, her strong advocacy skills are evident in her straightforward yet detailed presentation of the facts.

Louise is a member of the firm's Tax Group, Co-Chair of the Tax Litigation Group, and Co-Chair of the Charity and Not-for-Profit Law Group. She practises almost exclusively in the area of tax litigation. She provides support and advocacy at the audit stage, through the objection procedure and in court if necessary. Louise also has extensive experience advising clients on transfer pricing, goods and services tax, provincial tax and federal income tax and charity law issues. 

She has appeared in the Tax Court of Canada, the Federal Court of Appeal, the Ontario Superior Court and the Ontario Court of Appeal. Louise was formerly the Chair of the Student Committee for the firm and is currently Co-Chair of the firm's Women's Initiative.

Louise has been with Aird & Berlis since summering with the firm in 1987. 


Awards & Recognition

  • Recognized in Who’s Who Legal Corporate Tax: Controversy and Who's Who Legal: Canada as a leading Canadian tax lawyer
  • Named in Legal Media Group's Tax Advisors Expert Guide and Guide to the World's Leading Women in Business Law
  • Recognized for legal ability and high ethical standing by Martindale-Hubbell

Professional Involvement


  • The Advocates' Society
  • Canadian/Ontario Bar Association
  • Canadian Tax Foundation
  • Thomas More Lawyers' Guild of Toronto
  • Women Presidents' Organization (2004 - 2009)

Community Involvement

  • Birthright International, Board of Directors
  • Philip Aziz Centre for Hospice Care, Chair, Board of Directors

Teaching Engagements

  • Co-creator and former adjunct professor of "The Course of a Transaction," Osgoode Hall Law School

Representative Matters

Successfully represented a group of investors in the Tax Court and the Federal Court of Appeal in R. v. Landrus, which considered the applicability of the general anti-avoidance rule to a transaction which resulted in the claiming of a terminal loss

Successfully represented City Water International Ltd. before the Tax Court and Federal Court of Appeal, successfully arguing that installers and maintenance repair workers were independent contractors and not employees

Successfully represented Velcro Canada Inc. in the Tax Court of Canada on the meaning of "beneficial owner" under the Canada - Netherlands Income Tax Convention

Successfully argued an appeal in the Ontario Superior Court for Sun Microsystems Canada Inc. relating to the applicability of retail sales tax to warranty repair parts

Overturned multi-million dollar GST assessments against non-resident GST registrants because of issues relating to audit methodologies

Represented various Ontario hospitals, including William Osler Health Centre, on appeals before the Ontario Superior Court on the subject of whether computers used in medical recording are exempt "medical equipment" for sales tax purposes, leading to substantial settlement for all

Facilitated a resolution for a private company on a proposed reassessment to deny the deductibility of multimillion-dollar insurance fees paid to an offshore captive insurance company

Successfully advocated "due diligence" on behalf of various individuals who were alleged to have director's liability for GST and/payroll taxes

Successfully represented Mediclean Inc. in the Tax Court, overturning a CRA assessment for EI and CPP when the Court found workers to be independent contractors and not employees

Successfully represented a taxpayer at audit on the issue of whether stock trades were on income or capital account

Successfully negotiated numerous voluntary disclosures to eliminate penalties in relation to unreported foreign income

Selected Speaking Engagements

Presenter, “What’s New at CRA/Real Estate Transactions,” Professional Accountants PD Network, February 5, 2019.

Presenter, “What’s New at CRA?,” AJAG Presentation, November 22, 2018.

Presenter, “What's New at the CRA,” Education Consortium, October 24, 2018.

Presenter, "CRA Bag of Tricks: An Update on Audit Initiatives, Voluntary Disclosures and Recent Case Law," AJAG Seminar, October 27, 2017.

Presenter, "Topical Tax Issues and Recent Cases," AJAG Seminar, November 1, 2016.

Presenter, "CRA Real Estate Audit Project – The Scary Truth," Aird & Berlis LLP Seminar, June 1, 2016.

Presenter, "Tax Litigation - Tips & Traps," AJAG Seminar, January 20, 2016.

Presenter, "Tax-A Mixed Bag of Things You Need to Know," Education Consortium, November 11, 2015. 

Presenter, "Settlements: Tax Traps For The Unwary," Aird & Berlis LLP Seminar, January 28, 2015.

Presenter, "Tax Litigation: Navigating the Process From Audit Through Appeal," AJAG Seminar, January 15, 2015.

Presenter, "Update on Tax Litigation," Aird & Berlis LLP Tax Breakfast, October 1, 2013.

Presenter, "Update on Tax Litigation," Aird & Berlis LLP Tax Breakfast, September 11, 2012.

Presenter, "Velcro Canada Inc. v. R.," Ontario Bar Association (Taxation Law - Spring Blooms), April 26, 2012.

Presenter, "Requirements to Establish an Employer - CRA Independent Contractor Relationship, Ontario Painting Contractors Association, December 2011.

Presenter, "Update on Tax Litigation," Aird & Berlis LLP Tax Breakfast, September 14 & 20, 2011.

Speaker, "Avoiding Critical Tax Traps for Litigators," Spring Symposium, May 12, 2011.

Speaker, "Beneficial Ownership: Where do we stand?" International Fiscal Association (British Branch) Meeting, May 21, 2009.

Speaker, "Current Issues in Tax Litigation," Etobicoke Chartered Accountants Association's Tax Update, March 3, 2009.

Co-presenter with David Malach, "Tax Litigation Update," Aird & Berlis LLP Tax Breakfast, January 2009.

Co-presenter with David Malach, "Recent Issues and Updates," Aird & Berlis LLP Tax Breakfast, September 2007.

Co-presenter with Melanie Yach and David Malach, "Minimizing and Managing Litigation in Your Estate Planning Practice," Aird & Berlis LLP Tax Breakfast, March 2007.

Speaker, "Voluntary Disclosure: Tax Tips for Non-Tax Lawyers," Aird & Berlis LLP CLE, February 27, 2007.

Speaker, "Succession Planning," Burlington Seminar, December 7, 2006.

Speaker, "Reorganization - Tips & Traps, Accounting Negligence, Tax Cases, Voluntary Disclosures, Managing Tax Audits," Aird & Berlis LLP Tax Breakfast, October 12, 2006.

Speaker, "Tax Litigation Update," Aird & Berlis LLP Tax Breakfast, June 2006.

Co-presenter with David Malach, "When to Run to the Tax Department," Aird & Berlis LLP Articling Student Seminar, March 9, 2006.

Selected Publications

"Changes Are Coming to the Voluntary Disclosures Program," Aird & Berlis LLP Tax News Flash, March 2, 2017.

"Ontario Reverses Land Transfer Tax Partnership Exemption," Aird & Berlis LLP Tax News Flash, February 22, 2016.

"Beneficial Ownership of Royalties – Tax Court Respects Corporate Form," The Bottom Line, February 2012.

"Beneficial Ownership: Another Canadian Victory for Taxpayers," Tax Profile, February 2012.

"CRA ''Targets High Net Worth' Individuals," June 7, 2011. 

"Canada’s Transfer Pricing Rules," February 2011.

"GAAR – Common Sense Prevails," The Bottom Line, June 2009.

"The Murky Waters of Director's Liability after Corporate Revival," The Bottom Line, May 2009 (co-written with articling student Diana Yeung).

"Taxpayer Prevails – Again – on Beneficial Ownership," The Bottom Line, April 2009 (co-written with Barbara Worndl).

"Another Part to the Sales Tax Exemption for Manufacturers," The Bottom Line, January 2009.

"'More Than Five Full-Time Employees' – The Sensible Approach to Defining a Term," The Bottom Line, Mid-November 2008.

"More Treaty Interpretation: What is a Fixed Place of Business?" The Bottom Line, Mid-October 2008.

"Redeemer Foundation; confirming the CRA's Broad Audit Power," The Bottom Line, October 2008 (co-written with Milo Prelevic).

"When is a Foreign Worker Remunerated in Canada?" The Bottom Line, August 2008.

"Scholarship Programs do not give Rise to Taxable Benefits," The Bottom Line, July 2008.

"Beneficial Ownership by Holding Company Respected," The Bottom Line, June 2008.


Publications Article Feb 27, 2018 Highlights of the 2018 Federal Budget


  • LLB, University of Windsor, 1988
  • BA (Hons., with Distinction), English, Glendon Campus, York University, 1984
  • BA, English, St. Michael's College, University of Toronto, 1983