Ad Valorem is a Montreal-based firm that provides Canadian tax services to corporations with a strong focus on technology.

If your organization wants to manage employee expense reports using our Advataxes software/app, or if you need assistance with filing Goods and Services Tax/Harmonized Sales Tax or Quebec Sales Tax returns, filing corporate tax returns as a non-resident, or if you have any technical tax questions, please contact us.

With over 30 years of experience in Canadian VAT taxes, Serge launched Ad Valorem in 2011. Prior to launching the company, Serge not only served as a commodity tax manager of a major tobacco company (2008-2010), but was also the Chair of the commodity tax committee for the Tax Executive Institute (Montreal chapter).

In addition, Serge was a senior manager for a "big four" accounting firm (2001 - 2007), a tax recovery consultant in a Boutique (1994 - 2001) and worked for a railroad company as a sales tax analyst from 1992 to 1994.
- CPA, Society of Québec, 1990
- B. Com., UQAM, 1989
- B. Sc., Concordia University, 1985
- Québec Sales Tax Restrictions: The 26 Year Temporary Tax Measure (GST & Commodity Tax News, Carswell, November 2017, Vol. XXXI No. 9)
- HST New Housing Rebate Granted to a Person with Visitor Status (GST & Commodity Tax News, Carswell, May 2017, Vol. XXXI No. 4)
- Phasing Out Restricted ITRS for QST Starts in 2018 (GST & Commodity Tax News, Carswell, March 2017, Vol. XXXI No. 2)
- Déficit 1 G$ : une taxe harmonisée n’est pas une option pour le moment, dit Doherty (Radio-Canada, November 28th 2016)
- Suivez-vous la bonne carte routière - Récentes décisions en matière de répartition des intrants (June 2016, page 32)
- A new spin on apportionment of ITCs (GST & Commodity Tax News, March 2016, Vol. XXX No. 2)
- Quebec Losing on Online Sales (GST and Commodity Tax News, Carswell, July/August 2015, Vol XXIX No. 4)
- CPA Quebec Supports HST in Quebec (GST and Commodity Tax News, Carswell, March 2015, Vol XXIX No. 2)
- Is there a 16% HST for Quebec Looming on the Horizon? (GST and Commodity Tax News, Carswell, June/July 2014, Vol XXVIII No. 6)
- Moderator for the Group of Canadian Indirect Tax Practitioners (2011-2012 and 2013-2014)
- TEI - Quebec, QC Liaison Committee - Activity Report (February 2010)
- APFF - Bromont, QC, "Optimisations des liquidités et des taxes indirectes" (May 2009)
- Comments to Quebec Government on Proposed Changes Relating to Aggressive Tax Planning (The Tax Executive, Vol 61 (2), March-April 2009)
- TEI - Quebec, QC, Liaison Committee - Activity Report (February 2009)
- CICA-Ottawa, Commodity Tax symposium - Hot Topics Panel (September 2001)
- The Standing Committee on Finance (Ninth report of) - "Increasing the small supplier threshold" (June 1994)
Serge Vanier
Olivier Vanier is a recent graduate of Concordia University. During the final two years of his studies, he attended the John Molson School of Business (JMSB), where he completed a Bachelor of Commerce in Management. His academic journey has provided him with a strong foundation in organizational strategy, leadership, and operational effectiveness. Olivier joined Ad Valorem in 2025 as Client Manager.
- Bachelor of Commerce (BComm), Management, John Molson School of Business, 2024
- Minor in Political Science, Concordia University, 2022
- Minor in History, Concordia University, 2020