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100 leading critical infrastructure operators in Ontario

Tamtam tracks 262 critical infrastructure operators headquartered in Ontario. This list ranks the 100 largest by number of employees on LinkedIn, led by TD, RBC and Scotiabank. Their median headcount is 3,745. Half of them were founded in 1974 or later. The most common headquarters are Toronto (47), Ottawa (9) and Mississauga (7).

🇨🇦 Ontario100 companiesUpdated Oct 24, 2026
#CompanyIndustryHeadquarters EmployeesFounded
1
TDcareers.td.com

A leading North American bank with a global presence, serving 22 million customers with a team of over 85,000 employees Providing legendary customer experiences

Banking 🇨🇦 Toronto 105,476 n/a
2
RBCrbc.com

Global financial institution focused on delivering leading performance through innovative solutions, exceptional client experiences, and community support initiatives in various countries

Banking 🇨🇦 Toronto 99,801 n/a
3
Scotiabankscotiabank.com

A global financial institution serving customers, families, and communities by providing advice, products, and services to help them achieve success

Banking 🇨🇦 Toronto 87,065 n/a
4
BMObmo.com

Financial institution offering banking services, career growth opportunities, learning programs, and a supportive culture for personal and professional success.

Financial Services 🇨🇦 Toronto 60,290 n/a
5
CIBCcibc.com

Providing reliable financial products/services with innovative tools, dedicated to helping clients achieve their goals Cultivating a culture of trust, teamwork, and accountability

Banking 🇨🇦 Toronto 47,865 n/a
6
Manulifemanulife.com

Global financial services group providing insurance, wealth management, and asset management solutions to millions of customers worldwide.

Insurance 🇨🇦 Toronto 34,375 n/a
7
Rogers Communicationsrogers.com

Provider of communication services, supporting everyday connections and ensuring seamless connectivity for work and personal needs, with a focus on customer satisfaction

Telecommunications 🇨🇦 Toronto 28,500 n/a
8
Loblaw Companies Limitedloblaw.ca

Largest Canadian retailer offering grocery, pharmacy, health, beauty, financial services, apparel, and recognized brands like President’s Choice and no name.

Retail 🇨🇦 Brampton 24,123 n/a
9
Canada Post / Postes Canadacanadapost-postescanada.ca

Nationwide postal service with extensive retail network, delivering parcels and mail to over 17 million Canadian addresses.

Freight and Package Transportation 🇨🇦 Ottawa 23,941 n/a
10
City of Torontotoronto.ca

Provides diverse public services to residents, businesses, and visitors, encompassing technology, finance, culture, and innovation, employing a large workforce across numerous divisions.

Government Administration 🇨🇦 Toronto 23,495 n/a
11
Intactintactfc.com

Providing insurance solutions to help individuals, businesses, and society thrive during good times and bounce back during challenging times

Insurance 🇨🇦 Toronto 21,693 1809
12
Canada Lifecanadalife.com

Providing financial protection, retirement and investment solutions, workplace mental health support, and community project investments to enhance Canadians' well-being.

Insurance 🇨🇦 Toronto 13,569 n/a
13
University Health Networkuhn.ca

Largest Canadian research hospital network specializing in patient care, medical research, education, and fundraising for advanced healthcare services.

Hospitals and Health Care 🇨🇦 Toronto 11,930 n/a
14
RBC Capital Marketsrbccm.com

Global investment bank providing specialized expertise in capital markets, banking, and finance to corporations, institutional investors, asset managers, and governments across international markets.

Investment Banking 🇨🇦 Toronto 11,098 n/a
15
Ontario Power Generationopg.com

Leading clean power generator advancing clean energy innovations, striving for a net-zero future with diverse electricity generation fleet in Ontario and the United States

Utilities 🇨🇦 Toronto 9,878 1999
16
City of Ottawa / Ville d’Ottawajobs-emplois.ottawa.ca

A diverse workforce providing essential programs and services for over one million residents in Ottawa, with a focus on customer service and community well-being

Government Administration 🇨🇦 Ottawa 9,194 1855
17
Toronto Transit Commission (TTC)ttc.ca

A leading transit system in Toronto, providing safe and reliable transportation to over 17 million customers daily through various modes

Urban Transit Services 🇨🇦 Toronto 8,829 1921
18
RBC Wealth Managementrbcwealthmanagement.com

Provides comprehensive wealth management, private banking, investment, and asset management solutions to high net worth individuals, families, and institutional clients across global markets.

Financial Services 🇨🇦 Toronto 8,748 1869
19
Unity Health Torontounityhealth.to

A health network in Toronto providing primary, community, specialized, and long-term care services, as well as investing in research and education

Hospitals and Health Care 🇨🇦 Toronto 8,686 2017
20
GFL Environmental Inc.gflenv.com

A leading North American provider of environmental services for solid waste, liquid waste, and soil remediation, focusing on customer service, safety, and compliance

Environmental Services 🇨🇦 Vaughan 8,244 n/a
21
Co-operatorscooperators.ca

Multi-line insurance, wealth management, and financial advisory services focused on community support, sustainability, and client-centered solutions across Canada.

Financial Services 🇨🇦 Guelph 8,074 1945
22
The Ottawa Hospitalottawahospital.on.ca

Innovative teaching and research hospital providing specialized care, developing new treatments, and improving patient care through community engagement and global impact

Hospitals and Health Care 🇨🇦 Ottawa 7,679 1998
23
Sunnybrooksunnybrook.ca

A leading teaching hospital affiliated with the University of Toronto, specializing in patient care, groundbreaking research, and inventing the future of healthcare

Hospitals and Health Care 🇨🇦 Toronto 7,599 1948
24
London Health Sciences Centre (LHSC)lhsc.on.ca

Acute care teaching hospital offering specialized clinical services, leading in discovery and innovation, providing exceptional patient care and training healthcare professionals

Hospitals and Health Care 🇨🇦 London 7,092 n/a
25
Hamilton Health Scienceshamiltonhealthsciences.ca

Healthcare organization delivering specialized cardiac, stroke, trauma, cancer, palliative, and pediatric care to southwestern Ontario and beyond.

Hospitals and Health Care 🇨🇦 Hamilton 6,690 n/a
26
TD Securitiestdsecurities.com

A leading global provider of integrated capital markets products and services, offering underwriting, advisory, market access, transaction banking, and investment solutions

Investment Banking 🇨🇦 Toronto 6,544 n/a
27
Metrolinxmetrolinx.com

Provincial agency managing regional transportation through GO Transit, UP Express, and PRESTO while executing the largest transit infrastructure expansion in Ontario history.

Urban Transit Services 🇨🇦 Toronto 6,444 n/a
28
Aecon Group Inc.aecon.com

Provides integrated construction solutions for civil, urban transportation, nuclear, utility, and industrial sectors, plus project development, financing, investment, and operations.

Construction 🇨🇦 Toronto 6,368 n/a
29
Purolator Inc.purolator.com

A leading Canadian provider of integrated freight, parcel, and logistics solutions, focusing on sustainable growth, community well-being, and delivering promises for over 50 years

Freight and Package Transportation 🇨🇦 Mississauga 6,230 1960
30
Trillium Health Partnersthp.ca

Leading hospital providing full range of acute care services, specialized programs, and community-based care Committed to delivering high-quality, accessible patient care

Hospitals and Health Care 🇨🇦 Mississauga 6,009 2011
31
Extendicareextendicare.com

A leading provider of senior care services in Canada, offering skilled nursing care, home health care, retirement living, and management services with a focus on quality, compassion, and excellence

Hospitals and Health Care 🇨🇦 Markham 5,980 1968
32
Bayshore HealthCarebayshore.ca

Providing personalized home and community healthcare services across Canada, supporting clients' independence and quality of life with customized care plans.

Hospitals and Health Care 🇨🇦 Mississauga 5,911 1966
33
Hydro Onehydroone.com

Electricity transmission and distribution across Ontario, ensuring reliable power delivery and supporting infrastructure for homes and businesses.

Utilities 🇨🇦 Toronto 5,671 1999
34
BMO Capital Marketscapitalmarkets.bmo.com

A leading North American financial services provider offering a complete range of investment and corporate banking products to clients worldwide

Investment Banking 🇨🇦 Toronto 5,451 n/a
35
Aviva Canadaaviva.ca

Leading provider of home, automobile, lifestyle, and business insurance serving 2.5 million customers across Canada with strong financial backing.

Insurance 🇨🇦 Markham 5,075 1835
36
Region of Peelpeelregion.ca

A diverse and inclusive organization in Peel Region delivering social services and infrastructure for residents and businesses, fostering a Community for Life

Government Administration 🇨🇦 Brampton 4,959 1974
37
St. Michael's Hospitalunityhealth.to

A leading hospital providing compassionate care, medical education in 27 disciplines, and research through the Keenan Research Centre for global impact

Hospitals and Health Care 🇨🇦 Toronto 4,868 1892
38
TD Insurancetdinsurance.com

A leading insurance provider in Canada, offering protection for over four million individuals and families through home, auto, life, and health insurance

Insurance 🇨🇦 Toronto 4,647 n/a
39
City Of Hamiltonhamilton.ca

The organization aims to provide high-quality public services for a healthy, safe, and prosperous community while fostering collective ownership and diversity

Government Administration 🇨🇦 Hamilton 4,633 n/a
40
CAMHcamh.ca

A leading teaching hospital in Canada focused on transforming lives through clinical care, research, education, and advocacy for mental health and addiction issues

Hospitals and Health Care 🇨🇦 Toronto 4,477 1998
41
Bruce Powerbrucepower.com

Operation of nuclear power plants generating clean, low-cost electricity supplying 30% of Ontario's power with strong community values.

Utilities 🇨🇦 Tiverton 4,414 2001
42
Definitydefinityfinancial.com

Parent company of several established Canadian property and casualty insurance brands focused on improving insurance for customers and communities.

Insurance 🇨🇦 Waterloo 4,398 n/a
43
LifeLabs Medical Laboratory Serviceslifelabs.com

A leading Canadian provider of diagnostic information and digital health systems, offering laboratory tests, genetics services, and online patient portals

Hospitals and Health Care 🇨🇦 Toronto 4,356 n/a
44
William Osler Health Systemwilliamoslerhs.ca

Health system with three hospitals serving 13 million residents, providing a wide range of services including inpatient, outpatient, urgent care, and specialty clinics

Hospitals and Health Care 🇨🇦 Brampton 4,350 n/a
45
CIBC Capital Marketscibccm.com

Providing support and expertise to help clients access capital, expand operations, and invest through tailored industry-leading solutions in financial markets globally

Capital Markets 🇨🇦 Toronto 4,231 n/a
46
Sinai Healthsinaihealth.ca

A leading academic health science centre focused on integrated care, innovative research, and educating future healthcare leaders for comprehensive patient care

Hospitals and Health Care 🇨🇦 Toronto 4,083 n/a
47
York Region (The Regional Municipality of York)york.ca

The company provides services to 12 million residents, 54,000 businesses, and 650,000 employees in a two-tier government structure

Government Administration 🇨🇦 Newmarket 3,799 n/a
48
Health | Santéontario.ca

Focused on protecting and strengthening publicly funded health care in Ontario by providing patient-focused, sustainable, and high-quality care for all residents

Government Administration 🇨🇦 Toronto 3,762 1999
49
Lakeridge Healthlakeridgehealth.on.ca

A comprehensive healthcare provider with multiple hospitals, specialty centers, and community services, committed to delivering high-quality care to the region

Hospitals and Health Care 🇨🇦 Ajax 3,760 1998
50
Canadian Blood Servicesblood.ca

Canada's national organization responsible for ensuring a secure and sustainable supply of blood and organs for transfusion and transplantation

Non-profit Organizations 🇨🇦 Ottawa 3,745 1998
51
ParaMed Home Health Careparamed.com

Provider of home care and wellness solutions in Canada since 1974, offering fully trained care providers, ongoing training, support programs, and a strong workforce focused on core values

Hospitals and Health Care 🇨🇦 Markham 3,524 1974
52
NAV CANADAnavcanada.ca

Operates Canada's civil air navigation service, ensures safe and efficient aircraft movement, provides air traffic control, weather briefings, and navigation aids

Airlines and Aviation 🇨🇦 Ottawa 3,416 1996
53
Libertyjobs.libertyenergyandwater.com

Provider of essential energy and water services, including clean, renewable power generation, with a focus on sustainability and customer satisfaction

Utilities 🇨🇦 Oakville 3,364 1988
54
Humber River Healthhrh.ca

Leading digital hospital in North America using technology and clinical expertise to improve patient care, reduce errors, and drive community academic healthcare advancements

Hospitals and Health Care 🇨🇦 Toronto 3,272 n/a
55
Niagara Healthniagarahealth.on.ca

Regional hospital system providing acute care services, research, and innovation to improve healthcare for residents in the Niagara region

Hospitals and Health Care 🇨🇦 St. Catharines 3,213 n/a
56
Mackenzie Healthmackenziehealth.ca

Regional healthcare provider in Southwest York Region with two hospitals and community-based services, offering a wide range of healthcare programs and services to the community

Hospitals and Health Care 🇨🇦 Richmond Hill 3,197 1963
57
goeasy Ltd.goeasy.com

A Canadian financial services company providing non-prime leasing, lending, and credit access to millions of Canadians while prioritizing employee culture and community initiatives

Consumer Services 🇨🇦 Mississauga 3,024 n/a
58
Ontario Health | Santé Ontarioontariohealth.ca

Government agency ensuring high-quality, patient-centred healthcare services across Ontario, promoting health equity and supporting healthcare professionals.

Hospitals and Health Care 🇨🇦 Toronto 3,020 2019
59
St. Joseph's Healthcare Hamiltonstjoes.ca

A values-based academic health science centre affiliated with McMaster University and Mohawk College, committed to providing integrated, compassionate care and advancing research and education

Hospitals and Health Care 🇨🇦 Hamilton 2,983 1890
60
RBC Insurancerbcinsurance.com

A market leader in insurance, offering a wide range of life, health, home, auto, travel, and wealth solutions to individuals and groups across Canada Additionally, providing reinsurance solutions globally

Insurance 🇨🇦 Mississauga 2,965 n/a
61
Mount Sinai Hospital (Toronto), Sinai Healthmountsinai.on.ca

Internationally recognized academic health sciences center providing exemplary patient care, nursing excellence, and top employer culture Flagship clinical programs available

Hospitals and Health Care 🇨🇦 Toronto 2,951 1923
62
North York General Hospitalnygh.on.ca

A leading community academic hospital in Canada offering a wide range of acute, ambulatory, and long-term care services with a focus on patient- and family-centered care

Hospitals and Health Care 🇨🇦 North York 2,917 1968
63
Canadian Coast Guard/Garde côtière canadiennecanada.ca

A federal agency that operates a civilian fleet and provides maritime services to Canadians, ensuring safe waters, environmental protection, and economic growth

Government Administration 🇨🇦 Ottawa 2,892 1962
64
Corus Entertainmentcorusent.com

Development and delivery of diverse multimedia content including television, radio, digital platforms, and streaming services for global audiences.

Broadcast Media Production and Distribution 🇨🇦 Toronto 2,864 1999
65
SE Healthsehc.com

A not-for-profit social enterprise providing knowledge, care, and support to help clients achieve health and wellbeing goals Serving over 20,000 Canadians daily

Hospitals and Health Care 🇨🇦 Markham 2,851 1908
66
Scotia Wealth Managementscotiawealthmanagement.com

Wealth management professionals offering investment services, wealth solutions, and comprehensive financial planning to affluent individuals, entrepreneurs, and families

Financial Services 🇨🇦 Toronto 2,809 n/a
67
Desjardins Insurancedesjardins.com

A financial group offering insurance products through Certas and Desjardins Financial Security, with agents in Ontario, Alberta, and New Brunswick

Insurance 🇨🇦 Aurora 2,797 n/a
68
Kingston Health Sciences Centrekingstonhsc.ca

Top Canadian hospital, advancing health care through patient care, medical research, and training future healthcare professionals for Southeastern Ontario.

Hospitals and Health Care 🇨🇦 Kingston 2,793 1849
69
CHEOcheo.on.ca

A global leader in pediatric health care and research, providing excellence in complex care, education, and community partnership for children and youth

Hospitals and Health Care 🇨🇦 Ottawa 2,784 1974
70
Porter Airlines Inc.flyporter.com

Elevates economy air travel experience, providing genuine hospitality with style. Operates Embraer and De Havilland aircraft across North America, including Canada, US, Mexico, Caribbean.

Airlines and Aviation 🇨🇦 Toronto 2,769 2006
71
Durham Region (The Regional Municipality of Durham)durham.ca

Durham Region provides a wide range of services to a group of diverse communities, including paramedics, recycling, water supply, transit, and social programs

Government Administration 🇨🇦 Whitby 2,624 1974
72
Southlake Healthsouthlake.ca

Delivering healthcare services to northern York Region and southern Simcoe County through advanced programs, exceptional staff, and a commitment to patient safety and quality care

Hospitals and Health Care 🇨🇦 Newmarket 2,601 n/a
73
TMX Grouptmx.com

Operate global capital and commodity markets, providing technology-driven solutions for businesses, investors, and traders to raise capital and prosper.

Financial Services 🇨🇦 Toronto 2,564 n/a
74
Scarborough Health Networkshn.ca

A leading healthcare organization in Scarborough, offering diverse programs and services, including nephrology, cardiac care, spine center, and medical training partnerships with universities

Hospitals and Health Care 🇨🇦 Scarborough 2,536 2018
75
Bank of Canadabankofcanada.ca

Central bank focused on maintaining low, stable inflation and promoting economic and financial welfare for Canada's overall economic health.

Banking 🇨🇦 Ottawa 2,496 1935
76
BMO Nesbitt Burnsbmo.com

A full-service investment and wealth advisory organization within a financial group, offering comprehensive services through a large network of Investment Advisors

Investment Management 🇨🇦 Toronto 2,478 1987
77
Scotiabank - Global Banking and Marketsgbm.scotiabank.com

A global wholesale bank providing expertise, experience, and dedication to meet business needs while adhering to social media disclaimer

Banking 🇨🇦 Toronto 2,464 n/a
78
Halton Healthcarelinktr.ee

A healthcare organization with three community hospitals providing services to nearly 400,000 residents in Halton Hills, Milton, and Oakville, focused on exemplary patient experiences

Hospitals and Health Care 🇨🇦 Oakville 2,461 1998
79
Meridian Credit Unionmeridiancu.ca

An organization focused on creating an empowering and collaborative workplace, prioritizing employee well-being, community involvement, and long-term member relationships

Banking 🇨🇦 Toronto 2,269 2005
80
RBC Investor Servicesrbcis.com

Provides investment servicing solutions to asset managers, owners, insurers, and financial institutions, focusing on asset protection and growth worldwide.

Financial Services 🇨🇦 Toronto 2,230 2006
81
Michael Garron Hospitaltehn.ca

A vibrant community hospital in East Toronto providing high-quality, patient-centred healthcare services along the continuum of care with strong partnerships

Hospitals and Health Care 🇨🇦 Toronto 2,219 1929
82
Royal Victoria Regional Health Centrervh.on.ca

Healthcare institution in Barrie, Ontario serving over 450,000 residents with specialized services like interventional radiology, stroke care, trauma, cancer, heart, child, and youth programs

Hospitals and Health Care 🇨🇦 Barrie 2,191 1897
83
Region of Waterlooregionofwaterloo.ca

Provides municipal services including transit, waste management, health, housing, and employs over 3,500 people in diverse roles.

Government Administration 🇨🇦 Kitchener 2,165 1973
84
FedEx Canadafedex.com

Global logistics and transportation provider with domestic and international shipping services, advanced tracking systems, automated customs clearance, and a dedicated transportation network

Freight and Package Transportation 🇨🇦 Mississauga 2,111 n/a
85
CIBC Melloncibcmellon.com

A Canadian company offering investment servicing solutions to institutional investors, with over C$26 trillion in assets under administration

Financial Services 🇨🇦 Toronto 2,088 1996
86
Grand River Hospitalwrhn.ca

Ontario's large community hospital in Kitchener - Waterloo, offering a wide range of medical programs and services with over 6000 team members

Hospitals and Health Care 🇨🇦 Kitchener 2,058 n/a
87
Fidelity Canadafidelity.ca

Providing trusted investment portfolios and financial services to Canadian individuals and institutions, supporting better financial futures nationwide.

Financial Services 🇨🇦 Toronto 2,052 1987
88
Niagara Regionniagararegion.ca

Providing essential municipal services including water, roads, waste collection, public safety, and housing to support a diverse community.

Government Administration 🇨🇦 Thorold 2,038 1970
89
Halton Regionhalton.ca

Providing high-quality programs and services supporting safe, healthy communities and economic growth across multiple municipalities in Halton Region.

Government Administration 🇨🇦 Oakville 1,992 1974
90
Oak Valley Healthoakvalleyhealth.ca

A leading Ontario community health care organization with two hospitals and a Reactivation Care Centre, providing high-quality, patient-centered care Funded by community donations

Hospitals and Health Care 🇨🇦 Markham 1,969 1990
91
Northbridge Financial Corporationcareers.nbfc.com

A leading Canadian commercial property and casualty insurance group offering innovative solutions to protect businesses and support communities nationwide for 100 years

Insurance 🇨🇦 Toronto 1,956 n/a
92
Dynacaredynacare.ca

Leading provider of health and wellness solutions in Canada through accurate diagnostic information, innovative technology, and specialized health services for individuals, insurance industry, workplaces, and diagnostics

Hospitals and Health Care 🇨🇦 Brampton 1,954 n/a
93
BMO Commercial Bankcommercial.bmo.com

A financial partner providing strategic financing plans and customized solutions, leveraging global resources with localized knowledge to help businesses succeed

Financial Services 🇨🇦 Toronto 1,917 n/a
94
Bell Technical Solutions

Specializing in installation and maintenance of telecommunications services, our goal is to enhance connectivity for Canadians through innovation and exceptional customer experience

Telecommunications 🇨🇦 Mississauga 1,908 1996
95
VON Canadavon.ca

A nonprofit organization providing innovative clinical, personal, and social support services for people to live comfortably in their own homes

Home Health Care Services 🇨🇦 Ottawa 1,879 1897
96
Toronto Hydrotorontohydro.com

Operate and maintain electricity distribution system serving nearly 793,000 customers, ensuring safe, reliable power supply in Toronto.

Utilities 🇨🇦 Toronto 1,861 1911
97
City of Markhammarkham.ca

Fast-growing city with diverse communities, strong tech industry, numerous corporate headquarters, quality infrastructure, and recognized as a top government employer.

Government Administration 🇨🇦 Markham 1,839 1792
98
EQ Bankeqbank.ca

A leading Canadian Challenger Bank offering high interest, fee-free banking services, and various lending and financial products to individuals and credit unions

Financial Services 🇨🇦 Toronto 1,837 1970
99
Health Sciences North/Horizon Santé-Nordhsnsudbury.ca

An integrated network providing high-quality patient care, research, teaching, and services in various medical specialties to communities in Northern Ontario

Hospitals and Health Care 🇨🇦 Sudbury 1,755 n/a
100
City of London, Canadalondon.ca

A large team of over 3000 employees in London delivering 100+ services, working together to build a better city for all

Government Administration 🇨🇦 London 1,749 n/a

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How this list is built

Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Oct 24, 2026.

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