| # | Company | Employees |
|---|---|---|
| 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. |
46,913 |
| 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 |
37,734 |
| 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 |
20,001 |
| 4 |
Mass General Brighammassgeneralbrigham.org
Integrated academic health system providing patient care, research, teaching, and community services through hospitals, insurance, and specialized medical centers. |
17,890 |
| 5 |
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 |
17,496 |
| 6 |
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. |
13,806 |
| 7 |
MassMutualmassmutual.com
Providing mutual life insurance and financial security services focused on community support, shared dependence, and long-term happiness. |
13,000 |
| 8 |
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 |
12,125 |
| 9 |
UMass Memorial Healthummhealth.org
Largest healthcare system in Central Massachusetts offering hospital care, outpatient services, medical training, research, and community health support. |
10,819 |
| 10 |
Dana-Farber Cancer Institutedana-farber.org
Providing expert, compassionate care to children and adults with cancer while advancing understanding, treatment, cure, and prevention. |
8,981 |
| 11 |
UMass Memorial Medical Centerummhealth.org
A trusted academic medical center in Central Massachusetts, providing comprehensive and award-winning care through cutting-edge technology and highly trained specialists |
7,256 |
| 12 |
Partners HealthCarepartners.org
Integrated healthcare system offering coordinated care, high-quality services, research, teaching, and community outreach through academic medical centers and various healthcare entities |
6,751 |
| 13 |
Baystate Healthbaystatehealth.org
Largest healthcare organization in western Massachusetts providing quality, compassionate care across hospitals, improving community health and economic impact. |
6,269 |
| 14 |
American Toweramericantower.com
Global provider of digital infrastructure supporting mobile and broadband networks, enabling connectivity, innovation, and bridging digital divides worldwide. |
6,111 |
| 15 |
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 |
6,018 |
| 16 |
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. |
5,812 |
| 17 |
Lahey Hospital & Medical Centerlahey.org
A physician-led, nonprofit group practice offering compassionate care, superior patient outcomes, personalized treatment plans, advanced technology, research, and medical education |
5,147 |
| 18 |
Kaleida Healthkaleidahealth.org
Leading healthcare provider in Western New York offering state-of-the-art technology, comprehensive services, and compassionate care to over one million patients annually |
5,060 |
| 19 |
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. |
4,070 |
| 20 | 4,065 | |
| 21 |
Atrius Healthatriushealth.org
Innovative healthcare leader offering connected care at 30 locations in eastern Massachusetts Focus on high-quality, patient-centered, cost-effective care for all |
3,776 |
| 22 |
Roswell Park Comprehensive Cancer Centerroswellpark.org
A comprehensive cancer center offering cutting-edge care, research, and education to reduce the cancer burden and set national standards |
3,751 |
| 23 |
Catholic Healthchsbuffalo.org
A non-profit healthcare system in Buffalo, NY, providing care through hospitals, primary care centers, and community ministries with a focus on inclusiveness and integrity |
3,725 |
| 24 |
Southcoast Healthsouthcoast.org
Community-based health delivery system with hospitals, behavioral health services, and advanced clinical care in Southeastern Massachusetts and Rhode Island |
3,701 |
| 25 |
Cambridge Health Alliancechalliance.org
Provides comprehensive health care through hospitals and specialty centers, serving over 140,000 patients in Boston's metro-north region. |
3,680 |
| 26 |
South Shore Healthsouthshorehealth.org
Not-for-profit health system providing primary and specialty care, hospital services, home health care, and wellness programs in Southeastern Massachusetts Partnered with leading medical centers |
3,653 |
| 27 |
Eastern Bankeasternbank.com
Provides banking, wealth management, and investment solutions for consumers and businesses across eastern Massachusetts, New Hampshire, Rhode Island, and Connecticut. |
2,498 |
| 28 |
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 |
2,441 |
| 29 |
McLean Hospitalmcleanhospital.org
A leading psychiatric hospital dedicated to treating mental health conditions, conducting innovative research, and providing education to improve patient outcomes |
2,296 |
| 30 |
Cape Cod Healthcarecapecodhealth.org
Leading healthcare provider on Cape Cod offering a range of medical services including hospitals, homecare, urgent care, specialty care, and more |
2,278 |
| 31 |
Granite Telecommunicationsgranitenet.com
A dynamic and rapidly growing company in the telecommunications market, providing high quality, cost-effective solutions to exceed customer expectations |
2,254 |
| 32 |
Lowell General Hospitallowellgeneral.org
A not-for-profit community hospital providing state-of-the-art medical and surgical services, with a compassionate team committed to putting patients first |
2,181 |
| 33 |
Rockland Trustrocklandtrust.com
A Massachusetts-based full-service commercial bank offering banking, investment, and insurance services to businesses and individuals through various branches and centers |
2,059 |
| 34 | 2,028 | |
| 35 |
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 |
1,967 |
| 36 |
Mass General Hospitalmassgeneral.org
A higher education company located in Cambridge, Massachusetts, United States, specializing in providing healthcare services and medical research at Mass General Hospital |
1,839 |
| 37 |
Berkshire Health Systemsberkshirehealthsystems.org
Leading healthcare provider in Berkshire County offering comprehensive services, including emergency care, surgery, cancer treatment, imaging, and a network of primary and specialty care providers |
1,833 |
| 38 |
Winchester Hospitalwinchesterhospital.org
A leading provider of comprehensive health care services in northwest suburban Boston, offering acute-care inpatient services and a wide range of outpatient services |
1,809 |
| 39 |
Worcestershire Acute Hospitals NHS Trustworcsacute.nhs.uk
Hospital-based healthcare services across three sites, serving over 600,000 people with outpatient, inpatient, emergency, and diagnostic care. |
1,700 |
| 40 |
Emerson Healthemersonhealth.org
Committed to personalized and excellent healthcare, we prioritize patients and their well-being, offering care and support throughout every stage of life |
1,607 |
| 41 |
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 |
1,514 |
| 42 |
Commonwealth Care Alliancecommonwealthcarealliance.org
Mission-driven healthcare organization providing integrated, person-centered care and innovative health plans for individuals with significant needs in Massachusetts. |
1,503 |
| 43 |
Beverly Hospitalbeverlyhospital.org
A full-service community hospital providing quality, patient-centered care to North Shore and Cape Ann residents, with a wide range of medical specialties available |
1,498 |
| 44 |
Mass General Brigham - Salem Hospitalsalem.massgeneralbrigham.org
Stay updated with important updates by following our new LinkedIn page Connect with us for information related to Salem Hospital |
1,450 |
| 45 |
Behavioral Health Network, Inc (BHN)bhninc.org
Non-profit community behavioral health agency providing services to children and families with mental illness, substance use disorders, and intellectual disabilities in Western Mass since 1938 |
1,336 |
| 46 |
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 |
1,324 |
| 47 |
Digital Federal Credit Uniondcu.org
A top-20 credit union with over one million members offering innovative technology, focusing on member experience excellence and promoting financial success |
1,317 |
| 48 |
Tufts Health Plantuftshealthplan.com
A health plan company dedicated to guiding and empowering individuals to lead healthier lives |
1,259 |
| 49 |
Tufts Medicinetuftsmedicine.org
A health system in Massachusetts that brings together providers to offer high-quality, cost-effective care, from serious illnesses to chronic conditions, throughout the region |
1,241 |
| 50 |
Lawrence Hospitalmerrimackhealth.org
A non-profit community hospital in the Merrimack Valley offering high-quality healthcare, advanced surgical center, ambulatory services, emergency care, and professional development programs |
1,215 |
| 51 |
Saint Vincent Hospitalstvincenthospital.com
Advanced healthcare facility in Worcester offering comprehensive services such as heart care, orthopedics, robotic surgery, and women & infants programs in a friendly atmosphere |
1,203 |
| 52 |
Global Partners LPglobalp.com
This company operates a network of terminals, gas stations, and retail stations in the Northeast and throughout the US, providing energy solutions and convenience to customers |
1,185 |
| 53 |
Milford Regional Medical Centermilfordregional.org
Comprehensive healthcare system including a medical center, physician group, and foundation, offering advanced procedures and technology in a warm, caring environment |
1,140 |
| 54 |
Cooley Dickinson Hospitalcooleydickinson.org
An acute care community hospital providing exceptional and compassionate care focused on serving the Pioneer Valley in Western Massachusetts |
1,120 |
| 55 |
Holy Family Hospitalholyfamilyhospital.org
Providing high-quality healthcare services for over 60 years, with two campuses in Methuen and Haverhill serving the Merrimack Valley and southern New Hampshire |
1,075 |
| 56 |
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. |
1,040 |
| 57 |
Hebrew SeniorLifehebrewseniorlife.org
A nonprofit organization specializing in elder care, research, and housing for older adults in the Boston area, promoting healthy independent living |
1,035 |
| 58 |
The Cooperative Bank of Cape Codthecooperativebankofcapecod.com
A community bank on Cape Cod since 1921, prioritizing customer-centric service, earning recognition as Best Bank to Work For in 2020 |
951 |
| 59 |
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 |
946 |
| 60 |
Berkshire Bankberkshirebank.com
A relationship-driven bank providing financial expertise in New England and New York, offering tailored banking solutions through various divisions |
936 |
| 61 |
Holyoke Medical Centerholyokehealth.com
A non-sectarian hospital founded in 1893, now a 219-bed facility with 1,300 employees serving a population of 180,000 in various cities and towns |
931 |
| 62 |
NSTAR, now Eversource Energy- Follow our new company page, Eversource Energyeversource.com
A united energy company formed through a merger, focused on delivering reliable energy and superior customer service in New England |
923 |
| 63 |
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 |
903 |
| 64 |
Good Samaritan Medical Centerbmchealthsystem.org
An acute-care Catholic hospital offering inpatient, outpatient, emergency, orthopedic, oncology, cardiology, surgical, obstetric, and imaging services with Level III Trauma designation |
874 |
| 65 |
Signature Healthcare, MAsignature-healthcare.org
Integrated healthcare system with a community teaching hospital and multi-specialty physician group, committed to continuous process improvement and Lean management |
794 |
| 66 |
ISO New England Inc.iso-ne.com
Ensure reliable, competitively priced electricity supply across six New England states by managing complex grid operations and attracting skilled professionals. |
790 |
| 67 |
St. Elizabeth鈥檚 Medical Centerbmchealthsystem.org
Boston University teaching hospital providing advanced medical specialties such as cardiology, oncology, neurology, and orthopedics with respected physicians |
760 |
| 68 |
Brewster Ambulance Servicebrewsterambulance.com
A long-standing ambulance service in New England offering ALS, BLS, medical transportation, EMS training, and emergency 911 services, prioritizing quality and customer service |
759 |
| 69 |
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 |
758 |
| 70 |
Salem Five Banksalemfive.com
A long-standing financial institution offering sophisticated retail and commercial banking products and services through innovative technology to simplify customers' lives |
708 |
| 71 |
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 |
707 |
| 72 |
Welcome Airport Serviceswelcome-as.pl
The company is a leading airport handling agent in Poland, providing high-quality services to passenger and cargo airlines, with certifications and memberships in international aviation organizations |
702 |
| 73 |
Partners HealthCare at Home & Spaulding Rehabilitation Network Careersspauldingrehab.org
A company valuing diversity, talent, and compassion in providing exceptional care to patients worldwide, with a focus on employee well-being and growth |
694 |
| 74 |
Cataldo Ambulance Service Inc.cataldoambulance.com
A leading EMS provider offering emergency & routine medical services, ambulance & wheelchair transportation, education, mobile health programs, and COVID-19 vaccinations/testing in Massachusetts |
684 |
| 75 |
Anna Jaques Hospitalajh.org
Not-for-profit community hospital in Merrimack Valley, North Shore, and Southern New Hampshire, providing high quality medical care at a lower cost |
673 |
| 76 |
Salem Hospitalsalem.massgeneralbrigham.org
A leading healthcare provider on the North Shore, committed to exceptional quality, safety, and kindness Visit our careers page for opportunities |
669 |
| 77 |
Keolis Commuter Serviceskeolisna.com
Global leader in public transport operations, management, and innovation, providing transit solutions across various modes, including commuter rail networks |
668 |
| 78 |
One Communicationsonecommunications.com
One Communications is a regional provider of telecommunications services focused on delivering solutions for small and mid-sized businesses to help them communicate, save, and grow |
667 |
| 79 |
City of Lowelllowellma.gov
A diverse urban environment in Massachusetts, offering a mix of arts, culture, residential, and commercial opportunities at a strategic location |
665 |
| 80 |
Hallmark Health System, Inc.linkedin.com
This healthcare organization, formerly Hallmark Health, now operates as MelroseWakefield Healthcare Stay updated with their new LinkedIn page |
639 |
| 81 |
Cape Aircapeair.com
An employee-owned airline providing year-round service to beautiful destinations with exceptional customer service, convenient flight schedules, and smooth connections |
601 |
| 82 |
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 |
600 |
| 83 |
Lahey Healthlahey.org
Integrated healthcare services provider with nationally-recognized hospitals, primary care, specialist physicians, behavioral health, post-acute programs, and senior care resources in northeastern MA and southern NH |
595 |
| 84 |
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 |
592 |
| 85 |
Town of Andoverandoverma.gov
A suburban town in Massachusetts with a population of over 33,000 residents, offering quality municipal services, reputable schools, and accessible commuting options |
590 |
| 86 |
Middlesex Savings Bankmiddlesexbank.com
A $6 billion mutual bank founded in 1835, committed to serving the community with fair banking products, exceptional service, and support for local businesses |
586 |
| 87 |
UMass Memorial Health - Harringtonummhealth.org
Health care system serving over 25 communities in south central Massachusetts and northeastern Connecticut with hospitals, medical offices, physician services, urgent care, cancer center, and behavioral health programs |
584 |
| 88 |
Beth Israel Deaconess Hospital - Miltonbidmilton.org
A 100-bed community hospital providing inpatient and outpatient healthcare services, including emergency care and specialties like cardiology, orthopedics, and weight loss surgery |
562 |
| 89 |
Northern Banknbtc.com
A leading New England bank offering comprehensive banking solutions, community investment, and top-rated performance for businesses and individuals |
313 |
| 90 |
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 |
302 |
| 91 |
Carney Hospitalsteward.org
A community teaching hospital offering a wide range of medical specialties and services, known for clinical expertise and physician excellence |
288 |
| 92 |
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 |
238 |
| 93 |
Dedham Savingsdedhamsavings.com
A community-focused financial institution offering a wide range of banking services and support for individuals, families, and businesses |
199 |
| 94 |
Norfolk & Dedham Insurancendgroup.com
A group of mutual insurance companies offering protection for homes, autos, and businesses through a network of independent agents since 1825 |
167 |
| 95 |
Atlantic Power & Utilitiesatlanticpower.com
Independent power producer with assets in 11 US states and 2 Canadian provinces, selling energy to utilities and large customers under long-term agreements |
163 |
| 96 |
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 |
150 |
| 97 |
FirstLightfirstlight.energy
A leading clean power producer and energy storage company specializing in renewable energy solutions to accelerate the decarbonization of the electric grid |
143 |
| 98 |
Columbia Gas of Massachusetts, now Eversource. Please follow our company page, Eversourceeversource.com
The company is inviting people to follow their company page on Linkedin, offering an insight into Eversource Energy's services |
103 |
| 99 |
BankGloucesterbankgloucester.com
This company is dedicated to providing top-notch financial products and services to enhance clients' financial well-being and support local communities |
51 |
| 100 |
Agilitas Energyagilitasenergy.com
A leading developer and operator of renewable energy and energy storage systems in the Northeast and Texas, focusing on utility-scale projects |
47 |
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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 Massachusetts
- The largest companies in Massachusetts 3,093
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- IT Services and IT Consulting companies in Massachusetts 147
- Venture capital and private equity firms in Massachusetts 141
- Financial Services companies in Massachusetts 127
- Manufacturers in Massachusetts 119
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- Healthcare providers in Massachusetts 108
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- Venture Capital and Private Equity Principals companies in Massachusetts 107
- Biotechnology Research companies in Massachusetts 97
- IT services companies in Massachusetts 93
- AI-native companies in Massachusetts 88
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- Non-profit Organizations companies in Massachusetts 77
- Contract manufacturers in Massachusetts 69
- Energy companies in Massachusetts 69
- Medical Equipment Manufacturing companies in Massachusetts 69
The same list elsewhere in United States
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- Critical infrastructure operators in Alabama 116
- Critical infrastructure operators in North Carolina 109
- Critical infrastructure operators in Ohio 105
- Critical infrastructure operators in Michigan 93
- Critical infrastructure operators in New Jersey 91
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