These companies are the largest with in-house R&D in Boston. They represent a mix of established large enterprises and significant mid-sized firms. The selection includes GE, focused on aviation and energy, and Publicis Sapient, a digital business transformation partner. Healthcare is strongly represented by Massachusetts General Hospital and Boston Children's Hospital, while Wayfair operates in retail, and athenahealth offers IT solutions for healthcare.
A notable pattern among these companies is the strong presence of the healthcare and higher education sectors. Massachusetts General Hospital, Boston Children's Hospital, Dana-Farber Cancer Institute, Harvard Business School, and Harvard Medical School illustrate Boston's concentration of institutions dedicated to health and learning, many with long histories, such as Massachusetts General Hospital founded in 1811.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 | 99,488 | ||||
| 2 |
GE Vernovalinktr.ee
A purpose-built company focused on electrifying the planet and decarbonizing it through a diverse portfolio of energy businesses, ensuring reliable and sustainable energy |
70,646 | |||
| 3 |
Publicis Sapientpublicissapient.com
A digital business transformation partner, specializing in strategy, product, experience, engineering, data, and delivering impactful solutions to global organizations |
24,251 | |||
| 4 |
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 | |||
| 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 |
Wayfairaboutwayfair.com
Destination for all things home, offering expert customer service, tools for easy shopping, and wide selection to help create personalized spaces |
12,524 | |||
| 7 |
Harvard Business Schoolhbs.edu
Offers MBA, PhD, executive education, and online programs focused on leadership development, business practice, and entrepreneurship worldwide. |
12,457 | |||
| 8 |
Harvard Medical Schoolhms.harvard.edu
A prestigious medical school fostering a diverse community of leaders dedicated to advancing knowledge, education, and research to alleviate human suffering |
12,076 | |||
| 9 |
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 | |||
| 10 |
athenahealthathenahealth.com
The company strives to simplify healthcare with innovative technology for electronic health records, revenue cycle management, and patient engagement solutions |
8,956 | |||
| 11 | 8,184 | ||||
| 12 |
Toastpos.toasttab.com
Toast empowers restaurants with cloud-based software and hardware to streamline operations, drive revenue, and enhance guest experience through POS, marketing, and HR solutions |
7,762 | |||
| 13 |
Vertex Pharmaceuticalsvrtx.com
Global biotechnology company focusing on creating medicines for serious and life-threatening diseases, with a pioneering history in treating cystic fibrosis |
6,382 | |||
| 14 |
Dynatracedynatrace.com
This company specializes in providing a platform that unifies observability, business, and security data with AI-driven analytics and automation to optimize cloud operations and ensure flawless digital experiences |
6,090 | |||
| 15 |
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 | |||
Want more companies than this list?This page shows the largest ones only. Connect to Tamtam to see every company that matches, filter by size, industry or growth, and reach their decision-makers. | |||||
| 16 |
DraftKings Inc.careers.draftkings.com
The company is committed to creating popular games and betting experiences, leading the way in sports entertainment, innovation, and global collaboration |
5,760 | |||
| 17 |
Alexion Pharmaceuticals, Inc.alexion.com
Development of innovative medicines targeting rare diseases, focusing on complement system biology, expanding global reach to serve patients worldwide. |
5,112 | |||
| 18 |
Cabot Corporationcabotcorp.com
Global specialty chemical and performance materials company providing solutions to address current challenges and future customer needs worldwide. |
3,719 | |||
| 19 |
University of Massachusettsyoutube.com
Public university system offering high-quality education, conducting extensive research, and providing impactful public service to communities locally and globally. |
3,476 | |||
| 20 |
Rapid7rapid7.com
Global leader in AI-powered managed cybersecurity operations, advancing organizations' cyber resilience through integrating security data, AI, and threat intelligence to reduce risk and disrupt attackers. |
3,268 | |||
| 21 |
Suffolk Constructionsuffolk.com
National construction management firm providing real estate investment, design, self-perform construction, technology investment, and innovation research services across multiple industries. |
2,923 | |||
| 22 |
Klaviyoklaviyo.com
Unified customer platform empowering brands with ownership of consumer data to automate personalized email/SMS communications, foster customer relationships, and drive growth |
2,902 | |||
| 23 |
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 | |||
| 24 |
Semrushsemrush.com
A leading online visibility management platform offering a suite of marketing tools to help companies improve their online presence and results |
2,357 | |||
| 25 |
argenxargenx.com
Global immunology company focused on developing novel antibody-based medicines for severe autoimmune diseases through collaborations with leading researchers |
2,315 | |||
| 26 |
Curium Pharmacuriumpharma.com
Global leader in nuclear medicine, providing life-changing diagnostics and treatment for cancer patients worldwide through innovative radiopharmaceutical products and AI-driven solutions |
2,236 | |||
| 27 |
OutSystemsoutsystems.com
Provides an AI development platform for enterprises to rapidly build custom applications and AI agents while modernizing legacy core business systems. |
2,228 | |||
| 28 | 2,228 | ||||
| 29 |
InterSystemsintersystems.com
InterSystems provides data platforms and connected care solutions for healthcare, business, and government to drive better decisions and outcomes worldwide |
2,127 | |||
| 30 | 2,033 | ||||
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.
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 Nov 11, 2026.
More company lists in Boston
- The largest companies in Boston 1,089
- Multinational companies in Boston 241
- SaaS companies in Boston 193
- Software Development companies in Boston 145
- Financial services firms in Boston 127
- AI companies in Boston 123
- Professional services firms in Boston 104
- Venture capital and private equity firms in Boston 99
- Education providers in Boston 87
- Subscription businesses in Boston 87
- Financial Services companies in Boston 86
- Venture Capital and Private Equity Principals companies in Boston 78
- Companies with a mobile app in Boston 62
- Consulting firms in Boston 58
- Data and analytics companies in Boston 57
- IT Services and IT Consulting companies in Boston 56
- AI-native companies in Boston 51
- IT services companies in Boston 50
- Higher Education companies in Boston 48
- Investment Management companies in Boston 47
- Hospitals and Health Care companies in Boston 46
- Critical infrastructure operators in Boston 44
- Healthcare providers in Boston 42
- Non-profit Organizations companies in Boston 36
The same list elsewhere in United States
- Companies with in-house R&D in the United States 6,796
- Companies with in-house R&D in California 1,276
- Companies with in-house R&D in Texas 442
- Companies with in-house R&D in New York State 419
- Companies with in-house R&D in Massachusetts 396
- Companies with in-house R&D in Illinois 322
- Companies with in-house R&D in Michigan 287
- Companies with in-house R&D in Ohio 277
- Companies with in-house R&D in Pennsylvania 255
- Companies with in-house R&D in New Jersey 224
- Companies with in-house R&D in Florida 221
- Companies with in-house R&D in Alabama 214
- Companies with in-house R&D in Georgia 173
- Companies with in-house R&D in Virginia 166
- Companies with in-house R&D in North Carolina 158
- Companies with in-house R&D in Wisconsin 154
- Companies with in-house R&D in Minnesota 146
- Companies with in-house R&D in Washington State 140
- Companies with in-house R&D in Colorado 113
- Companies with in-house R&D in Maryland 107
- Companies with in-house R&D in Indiana 104
- Companies with in-house R&D in New York 223
- Companies with in-house R&D in San Francisco 147
- Companies with in-house R&D in Houston 129