Ad Valorem is a Canadian tax service provider on matters dealing with the Goods and Services Tax (GST), the Harmonized Sales Tax (HST), the Quebec Sales Tax (QST), the Canadian Corporate tax and the Quebec Corporate Tax. Our services range from consulting, tax compliance to representation to Canadian tax authorities. Ad Valorem is also the provider of the online employee expense software Advataxes that is designed to manage the GST, the HST & the QST.

Serge Vanier
With over 20 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
- 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)
Patricia Diaz
Patricia’s career is in the area of accounting and Canadian taxation. She graduated from George Brown Colllege in Accounting in 2013. Prior to Ad Valorem, she worked in the food industry. She joined Ad Valorem in 2016 where her focus has been on tax compliance management with both the Canada Revenue Agency and Revenu Quebec.