What Addendum does

Addendum is a privately held Quebec-based management and sustainability consultancy founded in 1987, organized as a senior collective of partners and associates rather than a traditional pyramid firm. The practice is split across three pillars — Strategy, Performance, and Human Capital — covering strategic planning, sustainability action plans, market research, process optimization, risk management, social impact measurement, change management, and bespoke training. Its packaged offering, Réverbère, formalizes SROI-based social impact measurement and strategic communication for municipalities, public institutions, nonprofits, foundations, and social economy enterprises.

The firm's competitive positioning rests on the operating experience of its partners — senior practitioners drawn from Desjardins, UPA, Bombardier Transport, L'Oréal, SAQ, Ordre des CPA du Québec, and Quebec cultural institutions — and on professional certifications including GRI Sustainability Professional, RIMS CRM, and Social Value Canada. Customers include Desjardins, Musée des beaux-arts de Montréal, Musée McCord Stewart, BAnQ, Ordre des CPA du Québec, UPA, Aliments du Québec, Festival CINEMANIA, Daily tous les jours, and Finance Montréal, with delivery concentrated in Quebec and ad hoc cross-border engagements.

The business model is professional services on a quote-based, engagement-by-engagement basis with no published pricing, no subscription product, no proprietary technology, and no external equity or debt funding disclosed. Distribution is direct consulting sales augmented by industry events, white papers, and affiliations with Fond Ecoleader, Chantier de l'économie sociale, Culture Montréal, and ACMQ. Headcount is small (11–50), government footprint is regional Quebec only, and there is no evidence of acquisition activity, international expansion, or capital markets activity across the data set.

Name

Addendum

Legal name

Addendum

Website

https://addendum.ca

Company type

Private

Founded year

1987

Operating status

Operating

Headcount range

11–50 employees

Short description

Addendum is a Quebec-based sustainability and management consultancy, founded in 1987, serving municipalities, nonprofits, cultural organizations, and enterprises with strategic advisory, SROI-based impact measurement via its Réverbère offering, and change management services through a senior partner collective.

Ownership category

akta.pro rank

Product category

Management Consulting

NAICS

Other Management Consulting Services (541618), Environmental Consulting Services (541620)

SIC

Services-Management Consulting Services (8742)

akta.pro primary industry

Organization Design & Change Management Consulting (BPAHACAD)

Keywords

• Sustainability consulting services
• Social impact measurement
• Strategic advisory services
• Organizational change management
• Sustainability strategy advisory

Headquarters

HQ city

Laval

HQ country

Canada

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Marketing or Sales, Others

Revenue model

1. Consulting Services: Professional consulting services in strategy, performance optimization, and human capital development. Services include strategic planning, sustainability action plans, business intelligence, market research, process optimization, social impact measurement (SROI), change management, training, and conferences.
2. Réverbère - Social Impact Measurement Service: Specialized service helping organizations measure and communicate their social impact. Combines rigorous social impact measurement with strategic communication to help clients demonstrate value to stakeholders.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels6 records

Core offering

Addendum is a sustainability-focused management consulting firm that helps organizations define their strategic vision, optimize positioning, deploy performance improvements, and manage human capital and change. Services span strategic planning, sustainability action plans, market intelligence, risk analysis, business intelligence, process optimization, social impact measurement (SROI), stakeholder consultation, training, and conferences. Its branded service Réverbère combines rigorous social impact measurement with strategic communication for municipalities, public institutions, nonprofits, and social enterprises.

Product overview

Addendum is a consulting firm offering strategic advisory services organized around three main practice areas: Strategy (strategic planning, sustainability action plans, market growth, risk analysis, brand positioning), Performance (business intelligence, market research, process optimization, social impact measurement/SROI, stakeholder consultation, sustainability assessment, responsible digital transformation), and Human Capital (organizational development, change management, conferences, training, development programs, strategic roadmap implementation). Their primary named service offering is Réverbère, a structured approach combining rigorous social impact measurement with strategic communication to help organizations reveal created value, inform decision-making, and build credible narratives around their actions.

Differentiator

Problem solved

Functional benefit

Brands

• Réverbère: A service offering that helps organizations see, measure, and communicate their social impact. Réverbère combines rigorous social impact measurement with strategic communication, helping municipalities, public institutions, non-profits, and social enterprises demonstrate their value created.

Products and services

• Réverbère Réverbère is a structured social impact measurement and strategic communication service that helps organizations see, measure, and communicate their social impact through rigorous impact assessment (SROI-based) and credible, mobilizing narratives. It is offered to municipalities, public institutions, nonprofits, social economy enterprises, community organizations, and foundations.
• Strategy Consulting Strategy practice area helping organizations define vision, optimize positioning, and capture opportunities for impact, growth, and diversification through strategic planning, sustainability action plans, market growth analysis, risk analysis, and brand positioning.
• Performance Consulting Performance practice area reinforcing organizational competitiveness through business intelligence, market research, process optimization, social impact measurement using SROI, stakeholder consultation, sustainability assessment, and responsible digital transformation.
• Human Capital Consulting Human Capital practice area facilitating organizational transformation through change management, conferences, custom training programs, development programs, and strategic roadmap implementation.

Quantifiable outcome

• Réverbère methodology provides framework to quantify social return on investment: 'For $1 invested in initiative Y, it's X $ in savings and/or multiple social benefits'

Named customers15 records

Segments7 records

Ideal customer profiles4 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Partnerships

14 partnerships are on record, tiered core and minor.

• La PiscinecoreStrategic or Co-development Partner · 1 May 2026Addendum collaborates with La Piscine for the second year on its micro-program in responsibility. Associates Fannie and Sophie will lead workshop #4 on the business plan integrating sustainability principles.
• Association des communicateurs municipaux du Québec (ACMQ)minorGTM or Marketing Partner · 1 May 2026Addendum launched its Réverbère service offering at the ACMQ 2026 Colloquium to introduce municipalities to social impact evaluation and communication.
• Daily tous les jourscoreStrategic or Co-development Partner · 1 January 2026Collaborative social impact study conducted by Addendum exploring the social impact and collective wellbeing generated by three interactive permanent installations in Budapest and Raleigh. Study examines how interactive public art can transform public spaces into inclusive meeting places.
• XnQuébeccoreStrategic or Co-development Partner · 1 January 2026Collaborated on a six-chapter white paper combining statistics, concrete data, practical tools, and inspiring case studies designed specifically for digital experience producers, offering a framework to identify sustainable innovation opportunities.
• CTEQ (Centre de transfert des entreprises du Québec)minorGTM or Marketing Partner · 1 January 2026Addendum-powered webinar hosted by CTEQ on sustainable business practices and responsible economy.
• Synergie Santé EnvironnementcoreStrategic or Co-development Partner · 1 January 2026Co-presented the Prix ÉLAN award recognizing organizations with impactful, far-reaching, and transformative initiatives. Partnership aims to support laureates in maximizing and sustaining new initiatives through strategic guidance.
• Global Reporting Initiative (GRI)coreOthersGRI Certified Sustainability Professional certification - Addendum team members hold GRI certifications for sustainability reporting.
• Social Value CanadacoreOthersCertified partner affiliated with Social Value Canada for social impact measurement and SROI methodology.
• RIMS (Risk Management Society)coreOthersRIMS CRM (Certified Risk Professional) certified team members. Affiliation with Risk Management Society for risk management expertise.
• Fond EcoleaderminorChannel Partner/ Reseller/ DistributorPartner status with Fond Ecoleader for eco-responsible business development in Quebec.
• Corporate Finance Institute (CFI)minorOthersTeam member certifications through Corporate Finance Institute for financial expertise.
• Chantier de l'économie socialeminorStrategic or Co-development PartnerAffiliation with Chantier de l'économie sociale supporting the social economy sector in Quebec.
• Ordre des CPA du QuébecminorOthersProfessional affiliation with the Quebec Order of Chartered Professional Accountants.
• Culture MontréalminorStrategic or Co-development PartnerAffiliation with Culture Montréal supporting cultural development in Montreal.

Scale indicators1 record

Recent moves6 records

Expansion highlights5 records

Emerging players

• Cossette Communication Group: Quebec-based integrated marketing and communications firm with a growing sustainability and social impact practice. Overlaps with Addendum's strategy, branding, and stakeholder communication work for Quebec clients.

Broad incumbents

• Anthesis Group: Global sustainability advisory firm providing ESG strategy, impact measurement, and reporting services. Comparable to Addendum in offering integrated sustainability advisory with measurement capabilities.
• BSR (Business for Social Responsibility): Global sustainability consultancy and network helping organizations with strategy, ESG, and human rights. Comparable to Addendum in the sustainability strategy and stakeholder consultation pillars, though with much larger global footprint.
• KPMG Canada - ESG Advisory: Big Four firm offering ESG strategy, sustainability reporting, and social impact services across Canada. Provides integrated services that overlap with Addendum's four-pillar methodology, especially for enterprise and government clients.
• Deloitte Canada - Sustainability & Climate Practice: Big Four firm with a large Canadian sustainability, ESG, and climate advisory practice. Competes with Addendum on sustainability strategy and impact reporting mandates, especially with larger Quebec and federal clients.

Others

• Fondation du Grand Montréal / EvalImpact: Quebec ecosystem organization for social impact evaluation. While not a direct competitor, it influences the procurement environment and capacity building in the same niche as Addendum's Réverbère service.
• Social Value Canada: National network and certification body for social value and SROI methodology. Addendum is a certified partner; comparable organizations in the Social Value International network represent both indirect competitors and ecosystem peers.

Regional players

• Centre for Social Innovation (CSI) - Consulting: Canadian non-profit advisory supporting social purpose organizations with strategy, impact measurement, and capacity building. Overlaps with Addendum's nonprofit and social economy segments, particularly in Ontario.

Direct peers

• Stratos (formerly Stratos Inc.): Canadian sustainability and social impact consultancy with deep Quebec and Ottawa presence. Directly comparable to Addendum in offering strategy, sustainability, and stakeholder engagement advisory to public, nonprofit, and corporate clients.
• Will Solutions: Quebec-based social impact measurement and SROI practitioner, closely aligned with Social Value Canada. Directly competes with Addendum's Réverbère service in measuring and communicating social impact for public and nonprofit clients.

Market position

Strengths4 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

• Facebookfacebook.com/profile.php?id=61576143927516
• LinkedInlinkedin.com/company/addendum/?viewAsMember=true
• Instagraminstagram.com/addendum.inc

Revenue estimate

Valuation estimate

Number of profiles

Profiles7 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Addendum