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54 leading critical infrastructure operators in Sydney

Tamtam tracks 54 critical infrastructure operators headquartered in Sydney. This list ranks all of them by number of employees on LinkedIn, led by Commonwealth Bank, Telstra and Macquarie Group. Their median headcount is 1,768. Half of them were founded in 1987 or later.

馃嚘馃嚭 Sydney54 companiesUpdated Oct 24, 2026
#CompanyIndustryHeadquarters EmployeesFounded
1
Commonwealth Bankcommbank.com.au

Leading provider of financial services in Australia, offering banking, funds management, insurance, investment, and sharebroking products to help individuals manage their finances

Financial Services 馃嚘馃嚭 Sydney 47,706 n/a
2
Telstratelstra.com.au

Providing technology and content solutions for a connected future, with a focus on customer experience and Australia's largest mobile network

Telecommunications 馃嚘馃嚭 Sydney 35,493 1901
3
Macquarie Groupmacquarie.com

Global financial services organization empowering people to innovate and invest for a better future in 34 markets Visit wwwmacquariecom for more information

Financial Services 馃嚘馃嚭 Sydney 20,757 1969
4
Westpacwestpac.com.au

A major banking institution in Australia and New Zealand, offering a wide range of financial services globally with a focus on customer prosperity

Banking 馃嚘馃嚭 Sydney 16,224 1817
5
Westpac Groupwestpac.com.au

Leading financial institution offering banking, wealth management, and customer-focused services across Australia, Asia, UK, and the US.

Financial Services 馃嚘馃嚭 Sydney 14,973 n/a
6
QBE Insuranceqbe.com

An international insurer offering commercial, personal, and specialty products in 27 countries to help manage risks and embrace change

Insurance 馃嚘馃嚭 Sydney 14,280 1886
7
IAGiag.com.au

Leading general insurance company in Australia and New Zealand, providing coverage under various brands, supporting communities in preventing and recovering from risks since 1851

Insurance 馃嚘馃嚭 Sydney 12,798 n/a
8
Ramsay Health Careramsayhealth.com

Provider of private hospitals, clinics, mental health, diagnostics, and community care services across multiple countries with extensive healthcare staff.

Hospitals and Health Care 馃嚘馃嚭 Sydney 11,896 1964
9
Sydney Trainstransport.nsw.gov.au

A leading transport organization in Sydney operates reliable trains, focusing on customer service, career progression, and maintaining a safe, efficient network

Rail Transportation 馃嚘馃嚭 Sydney 6,549 n/a
10
Origin Energyoriginenergy.com.au

Leading Australian energy company providing electricity, natural gas, solar, and LPG while focusing on affordability, sustainability, and carbon emissions reduction.

Utilities 馃嚘馃嚭 Sydney 6,250 2000
11
AGLagl.com.au

A leading energy company in Australia, dedicated to transforming how energy is produced, shared, and consumed through sustainability and innovation

Utilities 馃嚘馃嚭 Sydney 5,492 1837
12
NSW Police Forcepolice.nsw.gov.au

A leading police force in New South Wales, Australia, serving a population of seven million across land, sea, and air with community-based policing services

Law Enforcement 馃嚘馃嚭 Sydney 3,694 1862
13
Healius Limitedhealius.com.au

Provides affordable, accessible specialty diagnostic and pathology services across Australia through extensive laboratories and patient collection centers.

Hospitals and Health Care 馃嚘馃嚭 Sydney 3,531 n/a
14
Calvary Health Carecalvarycare.org.au

A charitable Catholic health care organization founded in 1885, providing compassionate and quality services to the most vulnerable populations across Australia

Hospitals and Health Care 馃嚘馃嚭 Sydney 3,336 1885
15
St.George Bankstgeorge.com.au

Provides retail and business banking services to over 2.6 million customers with extensive branch network and specialist financial advice.

Banking 馃嚘馃嚭 Sydney 3,327 n/a
16
Allianz Australiaallianz.com.au

Provider of personal, commercial, and corporate insurance products including general, workers' compensation, and life insurance in Australia and New Zealand.

Insurance 馃嚘馃嚭 Sydney 3,179 n/a
17
GenesisCaregenesiscare.com

Provider of integrated cancer care globally, focusing on personalized treatment experiences and access to radiotherapy, diagnostics, oncology, surgery, and clinical trials

Hospitals and Health Care 馃嚘馃嚭 Sydney 3,134 n/a
18
NSW Ambulanceambulance.nsw.gov.au

Provider of high quality out-of-hospital clinical care to over 725 million people in NSW through emergency responses and community safety programs

Hospitals and Health Care 馃嚘馃嚭 Sydney 2,840 1895
19
APA Groupapa.com.au

Ownership and management of a diverse $26 billion energy infrastructure portfolio delivering energy solutions across all Australian states and territories.

Utilities 馃嚘馃嚭 Sydney 2,804 2000
20
Estia Healthestiahealth.com.au

Provider of compassionate residential aged care with 70+ homes across Australia, delivering exceptional care and enriching experiences for residents.

Hospitals and Health Care 馃嚘馃嚭 Sydney 2,737 2005
21
Sonic Healthcaresonichealthcare.com

Internationally renowned healthcare provider specializing in pathology, radiology, and primary care with operations in multiple countries and a focus on quality medical diagnostic services

Hospitals and Health Care 馃嚘馃嚭 Sydney 2,328 1987
22
Qubeqube.com.au

Largest integrated provider of import and export logistics services across Australia, New Zealand, and Southeast Asia with extensive supply chain infrastructure.

Transportation, Logistics, Supply Chain and Storage 馃嚘馃嚭 Sydney 2,301 2011
23
Reserve Bank of Australiarba.gov.au

Australia's central bank contributes to price stability, full employment, and economic prosperity through setting cash rates, managing banknotes, and providing banking services

Banking 馃嚘馃嚭 Sydney 2,139 n/a
24
I-MED Radiology Networki-med.com.au

Australia's leading diagnostic imaging network offering a wide range of medical imaging and radiology services across 240 clinics nationwide

Hospitals and Health Care 馃嚘馃嚭 Sydney 2,033 n/a
25
Transgridtransgrid.com.au

The company operates and maintains high voltage transmission infrastructure in NSW and the ACT, leading the transition to clean energy for a sustainable future

Utilities 馃嚘馃嚭 Sydney 1,993 n/a
26
ASXasx.com.au

Leading global exchange offering trading, clearing, settlement, market insights, connectivity, and depository services across major asset classes with world-class financial infrastructure

Financial Services 馃嚘馃嚭 Sydney 1,991 1987
27
ING Australiaing.com.au

This company is a part of the ING Group, offering simple and value-driven banking products, 24/7 customer support, and a focus on improving customer's lives

Banking 馃嚘馃嚭 Sydney 1,768 1999
28
Western Sydney Local Health Districtnsw.gov.au

Delivering comprehensive healthcare to over a million residents in Western Sydney through top-notch clinical expertise, research, and compassionate care

Hospitals and Health Care 馃嚘馃嚭 Sydney 1,764 2011
29
Westpac Institutional and Businesswestpac.com.au

A partner in nation-building development, supporting clients in transitioning to net zero emissions and driving innovation and efficiency

Banking 馃嚘馃嚭 Sydney 1,754 1817
30
Colonial First Statecfs.com.au

provides superannuation, investment, and retirement products with expertise in Australian and global shares, property, fixed interest, and alternative assets

Financial Services 馃嚘馃嚭 Sydney 1,523 n/a
31
Alinta Energyalintaenergy.com.au

A leading Australian utility providing gas and electricity generation, retail, and wholesale services with a focus on renewable energy development

Utilities 馃嚘馃嚭 Sydney 1,342 n/a
32
Perpetual Limitedperpetual.com.au

Providing asset management, wealth management, and trustee services to clients across Australia, Asia, Europe, UK, and the United States.

Financial Services 馃嚘馃嚭 Sydney 1,309 1886
33
QantasLinkqantas.com

An entity operating in the airline industry

Airlines and Aviation 馃嚘馃嚭 Sydney 1,301 n/a
34
MLC Australiamlc.com.au

A financial services provider offering investments, superannuation, and wealth management solutions with a focus on empowering Australians financially throughout their lives

Financial Services 馃嚘馃嚭 Sydney 1,234 n/a
35
Sydney Metrosydneymetro.info

Revolutionizing Sydney's public transport with a network of four metro lines, 46 stations, and 113km of new rail by 2030

Rail Transportation 馃嚘馃嚭 Sydney 1,103 n/a
36
eftpos Payments Australiaeftposaustralia.com.au

Australia's debit card network processed 2 billion transactions in 2017, totaling $130 billion, offering a convenient payment solution for customers

Financial Services 馃嚘馃嚭 Sydney 916 2009
37
Ubankubank.com.au

digital platform providing real-time financial insights, spending tracking, and saving tools to help users manage money and achieve financial goals.

Financial Services 馃嚘馃嚭 Sydney 914 n/a
38
NSW Justice Health & Forensic Mental Health Networknsw.gov.au

Delivering healthcare to adults and young people in contact with forensic mental health and criminal justice systems in NSW

Hospitals and Health Care 馃嚘馃嚭 Sydney 898 n/a
39
Bupa Aged Care Australiabupaagedcare.com.au

Leading operator of residential aged care homes across Australia, with over 6000 committed employees providing quality care and innovative dementia support

Wellness and Fitness Services 馃嚘馃嚭 Sydney 841 n/a
40
WaterNSWwaternsw.com.au

The company manages and protects water sources, supplies bulk water, operates water systems, plans and delivers infrastructure, and provides customer water transaction services

Utilities 馃嚘馃嚭 Sydney 807 2015
41
Rabobank Australiarabobank.com.au

Specialist in food and agribusiness banking, providing customised solutions to clients globally, with a focus on sustainability, employee engagement, and diversity

Banking 馃嚘馃嚭 Sydney 796 1994
42
Cuscal Limitedcuscal.com

A payments and regulated data services provider in Australia, enabling banks, mutuals, corporates, and fintechs with innovative technology solutions for seamless customer connections

Financial Services 馃嚘馃嚭 Sydney 783 1966
43
Australian Digital Health Agencydigitalhealth.gov.au

Leading national efforts to improve health outcomes in Australia through delivery of digital healthcare systems and driving uptake of digital health technologies

Hospitals and Health Care 馃嚘馃嚭 Sydney 782 2016
44
Superloopsuperloop.com

Superloop unleashes the possibilities of the internet with carrier-grade networks, providing high-performance connectivity services for residential customers, businesses, and corporations in Australia

Telecommunications 馃嚘馃嚭 Sydney 771 2014
45
Challenger Limitedchallenger.com.au

Management of investment funds and life insurance products focused on providing customers with secure and reliable retirement income solutions.

Financial Services 馃嚘馃嚭 Sydney 718 1985
46
Macquarie Technology Groupmacquarietechnologygroup.com

An Australian company specializing in data center, cloud, cyber security, and telecom services for mid-large businesses and government clients Known for exceptional customer service

IT Services and IT Consulting 馃嚘馃嚭 Sydney 707 n/a
47
Tyro Paymentstyro.com

Provides integrated payment, banking, and lending solutions tailored for Australian merchants in hospitality, retail, services, and health sectors.

Financial Services 馃嚘馃嚭 Sydney 657 2003
48
CommSeccommsec.com.au

Australia's largest online broker providing online trading, cash management, margin lending, and international share trading Stay updated with live market news and expert analysis

Financial Services 馃嚘馃嚭 Sydney 639 1995
49
Chris O'Brien Lifehousemylifehouse.org.au

A not-for-profit cancer hospital offering comprehensive care, advanced treatments, holistic support, and cutting-edge research to improve patient outcomes and experiences

Hospitals and Health Care 馃嚘馃嚭 Sydney 638 2009
50
Whiddonwhiddon.com.au

A not-for-profit organization providing award-winning aged care services in NSW and QLD, focusing on individual needs and community connections

Hospitals and Health Care 馃嚘馃嚭 Sydney 611 1947
51
Australian Payments Plusauspayplus.com.au

An integrated Australian payment entity formed by BPAY Group, eftpos, and NPP Australia to create competitive, coordinated payment solutions for the future

Financial Services 馃嚘馃嚭 Sydney 559 n/a
52
Allianz Retire+allianzretireplus.com.au

An Australian company offering retirement products that combine insurance expertise with investment knowledge to provide security and stability for retirees

Insurance 馃嚘馃嚭 Sydney 63 2018
53
Zurich Australian Insurance Limitedzurich.com.au

Global financial services company in Australia offering insurance and investments under a single brand

Insurance 馃嚘馃嚭 Sydney 24 1959
54
UBS AG, Australia Branch

An investment banking company located in Sydney, Australia, offering a range of financial services from its Chifley Tower office

Investment Banking 馃嚘馃嚭 Sydney 12 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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