Mathieu St-Denis, CPA, CA

Executive summary

Mathieu St-Denis is a Chartered Professional Accountant with over 25 years of experience in the accounting and tax field. He completed the Canadian Institute of Chartered Accountants' technical In-Depth Tax Course and currently serves as the Domestic Tax Office Service Line Leader for BDO Ottawa/Gatineau and Eastern Ontario.

Mathieu focuses on delivering strategic tax services for medium to large-sized entities and high-net-worth families through comprehensive family office tax support. His knowledge and expertise spans across corporate structuring, succession and estate planning, domestic strategies, and international tax strategies. Mathieu also has deep experience in real estate tax planning—advising developers, investors, and property managers on structuring, compliance, and optimization.

He works closely with professionals in the medical, legal, and other professional service industries providing tailored advice that aligns with their business and personal tax objectives. He is highly experienced in trust and estate planning, including family trusts and alter-ego trusts.

Known for his clarity, practical insight, and client-first mindset, he delivers solutions that are both technically sound and strategically aligned. He was a Forty Under 40 honouree by the Ottawa Business Journal/Board of Trade in 2022.

In addition to his client work, Mathieu is a key contributor to BDO's culture in Ottawa and beyond—organizing internal events that promote collaboration, connection, and engagement across teams.

Mathieu will assist you in both French or English and can service clients in Quebec.

Professional affiliations

Member, CPA Canada
Member, CPA Québec
Member, CPA Ontario

Professional designations and education

Bachelor of Commerce, University of Ottawa (2005)
Diplôme d'études spécialisées supérieures, Université du Québec en Outaouais (2006)
Chartered Accountant (Ontario and Québec) (2008)
CICA In-Depth Tax Specialist (2011)