Tamtam Start free

36 leading critical infrastructure operators in Boston

Tamtam tracks 36 critical infrastructure operators headquartered in Boston. This list ranks all of them by number of employees on LinkedIn, led by State Street, Liberty Mutual Insurance and Massachusetts General Hospital. Their median headcount is 1,514. Half of them were founded in 1914 or later.

馃嚭馃嚫 Boston36 companiesUpdated Oct 24, 2026
#CompanyIndustryHeadquarters EmployeesFounded
1
State Streetstatestreet.com

Global financial leader providing comprehensive investment services, institutional asset management, multi-asset trading, and digital solutions to enhance portfolio performance and decision making.

Financial Services 馃嚭馃嚫 Boston 46,913 1792
2
Liberty Mutual Insurancelibertymutualgroup.com

Global leader in property and casualty insurance dedicated to fostering career growth, social responsibility, sustainability, diversity, and innovative solutions for customers worldwide

Insurance 馃嚭馃嚫 Boston 37,734 1912
3
Massachusetts General Hospitalmassgeneral.org

Dedicated to providing top-notch healthcare in a compassionate environment through innovative research and education, improving health in diverse communities served

Hospitals and Health Care 馃嚭馃嚫 Boston 20,001 1811
4
Boston Children's Hospitalchildrenshospital.org

A leading pediatric medical center providing comprehensive healthcare services for children from birth to 21 years, with specialized clinical programs and renowned physicians

Hospitals and Health Care 馃嚭馃嚫 Boston 17,496 1869
5
Santander USsantanderus.com

Provides auto, retail, commercial, and investment banking services alongside wealth management for millions of customers across various US hubs and global markets.

Financial Services 馃嚭馃嚫 Boston 13,806 1857
6
Beth Israel Deaconess Medical Centerbidmc.org

World-class teaching hospital in Boston, part of a health care system focused on expanding access to great care, advancing medicine through research and education

Hospitals and Health Care 馃嚭馃嚫 Boston 12,125 n/a
7
Boston Medical Center (BMC)bmc.org

delivering equitable healthcare, conducting research, and collaborating with communities to improve health outcomes and access for all patients

Hospitals and Health Care 馃嚭馃嚫 Boston 10,149 n/a
8
Dana-Farber Cancer Institutedana-farber.org

Providing expert, compassionate care to children and adults with cancer while advancing understanding, treatment, cure, and prevention.

Hospitals and Health Care 馃嚭馃嚫 Boston 8,981 1947
9
American Toweramericantower.com

Global provider of digital infrastructure supporting mobile and broadband networks, enabling connectivity, innovation, and bridging digital divides worldwide.

Telecommunications 馃嚭馃嚫 Boston 6,111 1995
10
Tufts Medical Centertuftsmedicine.org

Academic medical center offering exceptional care in New England, specializing in primary care, trauma, heart transplants, and various specialties Conducts medical research and education

Hospitals and Health Care 馃嚭馃嚫 Boston 6,018 1796
11
Veolia | North Americaveolianorthamerica.com

Provides resource management solutions including water decontamination, toxic waste handling, fossil fuel alternatives, wastewater reuse, and battery recycling for cities and industries.

Environmental Services 馃嚭馃嚫 Boston 5,812 n/a
12
Blue Cross Blue Shield of Massachusettsbluecrossma.org

Provides health insurance coverage to over 3 million members, focusing on community wellness, inclusivity, and employee development in Massachusetts.

Hospitals and Health Care 馃嚭馃嚫 Boston 4,070 1937
13
MBTAmbta.com

Operates comprehensive bus, subway, commuter rail, and ferry services across greater Boston, providing essential public transportation modes for millions of local residents.

Government Administration 馃嚭馃嚫 Boston 4,065 1897
14
Eastern Bankeasternbank.com

Provides banking, wealth management, and investment solutions for consumers and businesses across eastern Massachusetts, New Hampshire, Rhode Island, and Connecticut.

Banking 馃嚭馃嚫 Boston 2,498 1818
15
Spaulding Rehabilitation Hospitalspauldingrehab.org

A leading rehabilitation facility providing comprehensive treatment, part of a network with specialty hospitals, skilled nursing facilities, and outpatient centers in Eastern Massachusetts

Hospitals and Health Care 馃嚭馃嚫 Boston 2,441 1971
16
MassDOTmass.gov

The company partners with communities and agencies to support infrastructure programs in Massachusetts, focusing on enhancing transportation and improving residents' quality of life

Government Administration 馃嚭馃嚫 Boston 2,028 2009
17
Harvard Medical School and Massachusetts General Hospitalmassgeneral.org

A prestigious hospital affiliated with Harvard Medical School, offering clinical experience and clerkships while supporting a large research enterprise

Higher Education 馃嚭馃嚫 Boston 1,967 1811
18
Massachusetts Eye and Earmasseyeandear.org

Specialty hospital providing excellent care for disorders of the eye, ear, nose, and throat, while also focusing on education and research

Hospitals and Health Care 馃嚭馃嚫 Boston 1,514 1824
19
Commonwealth Care Alliancecommonwealthcarealliance.org

Mission-driven healthcare organization providing integrated, person-centered care and innovative health plans for individuals with significant needs in Massachusetts.

Hospitals and Health Care 馃嚭馃嚫 Boston 1,503 2003
20
Federal Reserve Bank of Bostonbostonfed.org

A leader in financial regulation and monetary policy, pioneering new payment strategies and using cutting-edge technology to ensure economic growth and stability

Financial Services 馃嚭馃嚫 Boston 1,324 1914
21
Santander USsantanderus.com

Diversified financial business providing retail banking, commercial loans, consumer finance, private wealth management, and investment banking services across the United States for millions.

Financial Services 馃嚭馃嚫 Boston 1,040 n/a
22
Brigham and Women鈥檚 Faulkner Hospitalbrighamandwomensfaulkner.org

A 171-bed non-profit community teaching hospital offering comprehensive care in various specialties, nationally recognized for best practices in patient care and safety

Hospitals and Health Care 馃嚭馃嚫 Boston 946 1900
23
Berkshire Bankberkshirebank.com

A relationship-driven bank providing financial expertise in New England and New York, offering tailored banking solutions through various divisions

Banking 馃嚭馃嚫 Boston 936 1846
24
New England Baptist Hospitalnebh.org

A leading regional provider of orthopedic surgery and musculoskeletal treatment, recognized for high patient satisfaction and clinical outcomes Collaborates with prestigious medical schools

Hospitals and Health Care 馃嚭馃嚫 Boston 903 1893
25
Massachusetts Port Authoritymassport.com

The company is focused on connecting Massachusetts and New England to the world through safe and efficient transportation, while also prioritizing diversity, sustainability, and community engagement

Government Administration 馃嚭馃嚫 Boston 758 1956
26
Keolis SAkeolisna.com

Leading provider of passenger transportation services in the US and Canada, offering train, bus, and ADA paratransit services through public contracts

Transportation, Logistics, Supply Chain and Storage 馃嚭馃嚫 Boston 731 n/a
27
Massachusetts Executive Office of Health and Human Servicesmass.gov

A health and human services organization in Massachusetts, working to promote health, resilience, and independence for residents through various programs

Government Administration 馃嚭馃嚫 Boston 707 n/a
28
Keolis Commuter Serviceskeolisna.com

Global leader in public transport operations, management, and innovation, providing transit solutions across various modes, including commuter rail networks

Truck Transportation 馃嚭馃嚫 Boston 668 2013
29
Joslin Diabetes Centerjoslin.org

A world-renowned diabetes center dedicated to finding a cure and improving treatment for diabetes, with a mission to prevent, treat, and cure diabetes

Hospitals and Health Care 馃嚭馃嚫 Boston 600 1898
30
Nexampnexamp.com

A leading company in the new energy economy, specializing in deploying and operating solar energy assets for a cleaner, more secure energy future

Solar Electric Power Generation 馃嚭馃嚫 Boston 592 2007
31
Vicinity Energyvicinityenergy.us

A clean energy company owning and operating district energy systems nationwide, providing reliable clean steam, hot water, chilled water, with a commitment to net zero carbon

Utilities 馃嚭馃嚫 Boston 302 2020
32
Starry, Inc.starry.com

This company offers lightning-fast internet service that is simple, innovative, and focused on making customers' internet experiences happier They are hiring diverse talent

Technology, Information and Internet 馃嚭馃嚫 Boston 238 2014
33
Advanced Poweradvancedpower.ch

A privately-owned company developing, owning, and managing power generation projects in Europe and North America with a focus on cleaner energy and reducing global emissions

Electric Power Generation 馃嚭馃嚫 Boston 150 2000
34
Kearsarge Energykearsargeenergy.com

A vertically integrated renewable energy project development and finance company that owns and operates solar and energy storage projects in the US

Solar Electric Power Generation 馃嚭馃嚫 Boston 28 2009
35
Greenvolt Power NAgreenvolt.com

An international wind & solar developer in North America, producing renewable electricity with experienced employees and a passionate management team

Renewable Energy Power Generation 馃嚭馃嚫 Boston 11 2022
36
NSTAR Electric Constar.com

An electric utility serving residential, commercial, and industrial customers in parts of Massachusetts, Connecticut, New Hampshire, and western Massachusetts

Utilities 馃嚭馃嚫 Boston 8 1886

Turn this list into pipeline

Tamtam finds the decision-makers at every company on a list like this one, with verified emails, phone numbers and the buying signals that tell you when to reach out.

Build your own list, free

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.

More company lists in Boston

The same list elsewhere in United States