This selection of private equity-backed companies in Massachusetts includes large firms, mainly in IT services and software development. athenahealth, with 8956 employees, simplifies healthcare with technology. Rocket Software assists organizations in transforming IT infrastructure. Curium Pharma, founded in 2017, is a global leader in nuclear medicine, while Duck Creek Technologies provides cloud-based software for the insurance industry.
The companies listed show a concentration in the Boston metropolitan area, with many headquartered in Boston, Waltham, or Wilmington. The prevalence of IT services and software development, alongside pharmaceutical manufacturing, indicates a strong focus on technology and healthcare sectors within this group.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
athenahealthathenahealth.com
The company strives to simplify healthcare with innovative technology for electronic health records, revenue cycle management, and patient engagement solutions |
8,956 | |||
| 2 |
Rocket Softwarerocketsoftware.com
Partner for organizations transforming IT infrastructure, applications, and data from core systems to cloud with global support and innovation. |
4,385 | |||
| 3 |
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 | |||
| 4 |
Duck Creek Technologiesduckcreek.com
Provides cloud-based software solutions for property, casualty, and general insurance industries enabling agile, intelligent, and transparent insurance operations. |
1,904 | |||
| 5 | 1,861 | ||||
| 6 |
Black Duckblackduck.com
Provides comprehensive software security solutions that manage risks, ensure compliance, and enable innovation for regulated, AI-driven environments. |
1,295 | |||
| 7 | 1,109 | ||||
| 8 |
SMYK Groupsmykgroup.com
A renowned brand offering children's products in Poland, with stores and an online shop, focused on customer satisfaction and product quality |
1,090 | |||
| 9 |
Centerlinecenterlinecommunications.com
Designs, builds, and maintains wireless, wireline networks, and infrastructure facilities for Fortune 500 clients across the US Owned by Audax Private Equity |
959 | |||
| 10 |
Power Factorspowerfactors.com
Unified renewable energy operations with hardware, software, and services, managing extensive wind, solar, and storage assets globally for optimized performance. |
632 | |||
| 11 |
Salsifysalsify.com
Salsify's Product Experience Management platform helps brand manufacturers, distributors, and retailers succeed in digital commerce through PIM, Syndication, and Automation |
583 | |||
| 12 |
Chase Corporationchasecorp.com
A leading manufacturer of protective materials for high reliability applications, offering industrial coatings, tapes, adhesives, and sealants globally under trusted brand names |
481 | |||
| 13 |
Bartlett Nuclearbartlettnuclear.com
A leading provider of radiation safety personnel to the US nuclear power industry, offering technical services, facilities maintenance, engineering, training, and environmental services |
475 | |||
| 14 |
Black Diamond Networksblackdiamondnet.com
The company deploys skilled consultants in regulated industries for quality, compliance, and innovation, emphasizing speed, precision, and dynamic solutions |
473 | |||
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. | |||||
| 15 |
AMAG Pharmaceuticalsamagpharma.com
Develops and delivers innovative medicines to address complex, underserved health conditions, and invests in clinical research to improve patient care. |
368 | |||
| 16 |
Millstone Medicalmillstonemedical.com
Millstone Medical provides post-manufacturing and aftermarket services to medical device manufacturers, focusing on quality, compliance, and business success |
364 | |||
| 17 |
Biodeal Pharmaceuticals Limitedbiodealpharma.com
Contract Development Manufacturing Organization offering diverse pharmaceutical formulations including nasal sprays, injectables, solid orals, nutraceuticals, and dermocosmetics for global clients. |
346 | |||
| 18 |
bluebird biolinkedin.com
This company focuses on developing curative gene therapies for severe genetic diseases like sickle cell, thalassemia, and cerebral adrenoleukodystrophy |
316 | |||
| 19 |
Keystone Partnerskeystonepartners.com
This company provides comprehensive career management services, including outplacement, leadership development, coaching, succession planning, and retirement planning for individuals and organizations |
240 | |||
| 20 |
Corza Wound Closurecorza.com
A leading provider of advanced surgical products and technologies, offering high performance sutures, microsurgical knives, and OEM components worldwide |
222 | |||
| 21 |
Fiduciary Trust Companyfiduciary-trust.com
Private wealth management firm offering objective advice and services for families, individuals, nonprofits, financial advisors, and single-family offices Specializes in wealth planning and investment management |
199 | |||
| 22 |
oneZero Financial Systemsonezero.com
Technology company developing trading solutions for financial institutions globally with high reliability, scalability, and performance, handling billions in transactions daily |
189 | |||
| 23 |
Lacerta Group, LLC.lacerta.com
A leading provider of thermoformed packaging solutions offering PET and sustainable packaging with in-house design capabilities and commitment to quality and sustainability |
187 | |||
| 24 |
Vanguard Renewablesvanguardrenewables.com
A national leader in food waste recycling, Vanguard Renewables develops organic waste-to-energy projects to reduce greenhouse gas emissions and support regenerative agriculture |
181 | |||
| 25 |
Engagewareengageware.com
Provider of customer engagement solutions powered by AI to automate responses, improve customer experience, reduce call center workload, and drive growth for businesses |
114 | |||
| 26 |
CKEditorckeditor.com
A leading creator of rich text editing software offering customizable and collaborative solutions for developers worldwide, with a strong focus on employee satisfaction |
90 | |||
| 27 |
Momentum Enterprisesthemomentumenterprises.com
An asset management company focused on community, family, and children, operating 17 businesses in New England, specializing in turning underperforming organizations into top-tier businesses |
37 | |||
| 28 |
B&E Groupbegroupllc.com
A company specializing in manufacturing machined components for aerospace, military, and space applications, as well as repairing commercial aerospace engine components |
35 | |||
| 29 |
AlphaStruxurealphastruxure.com
Energy as a Service provider specializing in designing, building, owning, and operating customized energy infrastructure, including microgrids, with a focus on sustainability and cost stability |
26 | |||
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 15, 2026.
More company lists in Massachusetts
- The largest companies in Massachusetts 3,418
- Multinational companies in Massachusetts 637
- Companies with in-house R&D in Massachusetts 396
- SaaS companies in Massachusetts 339
- Education providers in Massachusetts 313
- Software Development companies in Massachusetts 273
- Manufacturers in Massachusetts 269
- Professional services firms in Massachusetts 249
- AI companies in Massachusetts 243
- Financial services firms in Massachusetts 235
- Healthcare providers in Massachusetts 213
- Hospitals and Health Care companies in Massachusetts 197
- Hardware manufacturers in Massachusetts 196
- Subscription businesses in Massachusetts 183
- IT Services and IT Consulting companies in Massachusetts 176
- Retail chains in Massachusetts 167
- Critical infrastructure operators in Massachusetts 165
- Companies with a mobile app in Massachusetts 159
- Higher Education companies in Massachusetts 158
- Venture capital and private equity firms in Massachusetts 157
- IT services companies in Massachusetts 155
- Consulting firms in Massachusetts 153
- Financial Services companies in Massachusetts 153
- Pharmaceutical companies in Massachusetts 143
The same list elsewhere in United States
- Private equity-backed companies in the United States 579
- Private equity-backed companies in Texas 75
- Private equity-backed companies in California 72
- Private equity-backed companies in New York State 45
- Private equity-backed companies in Florida 44
- Private equity-backed companies in Illinois 33
- Private equity-backed companies in North Carolina 25
- Private equity-backed companies in New York 39