These are private equity-backed companies in Illinois, mostly large and mid-sized firms. The list includes businesses like Walgreens, a retail pharmacy chain, HUB International, an insurance advisor, and Baker Tilly US, an advisory CPA firm. Other notable companies are HAVI, a global supply chain solutions provider, and Cision, specializing in media intelligence. Many of these firms are headquartered in Chicago.
The companies here show a concentration in professional services, with several in insurance, accounting, and business consulting. For instance, AssuredPartners is a global insurance brokerage, and Sikich offers technology solutions and financial services. There is also a significant presence of software development companies, such as Applied Systems, which provides cloud software for the insurance industry, and Relativity, a SaaS product for data organization.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
Walgreenswalgreens.com
A leading retail pharmacy offering health and beauty products, with a focus on providing pharmacy services and a seamless omnichannel experience for customers |
90,723 | |||
| 2 |
HUB Internationalhubinternational.com
Advises businesses and individuals on insurance, risk management, employee benefits, retirement, and wealth management with tailored solutions. |
16,129 | |||
| 3 |
Baker Tilly USbakertilly.com
A leading advisory CPA firm with a coast-to-coast and global presence, part of Baker Tilly International network with 43,000 professionals |
10,594 | |||
| 4 | 4,160 | ||||
| 5 |
Cisioncision.com
A global leader in media intelligence and communication solutions, equipping professionals with tools to excel in today's data-driven world |
3,839 | |||
| 6 |
AssuredPartnersajg.com
Global insurance brokerage specializing in industry-specific solutions for businesses and consumers, offering services in commercial insurance, risk management, and employee benefits |
3,075 | |||
| 7 |
AIT Worldwide Logisticsaitworldwide.com
Global freight forwarding company offering customized supply chain solutions including sea, air, ground, rail transport, customs clearance, and warehousing. |
2,822 | |||
| 8 |
Applied Systemswww1.appliedsystems.com
A leading provider of innovative cloud software for the insurance industry, driving transformation through digitization, automation, and new partnerships |
2,813 | |||
| 9 |
Chamberlain Groupchamberlaingroup.com
A global leader in intelligent access technology, providing seamless, secure access to homes and businesses through innovative products and software solutions |
2,781 | |||
| 10 |
Sikichsikich.com
A global professional services company specializing in technology solutions, delivering transformative digital strategies and financial services to various clients worldwide |
2,335 | |||
| 11 |
Relativityrelativity.com
A software company offering RelativityOne, a SaaS product for data organization, truth discovery, and action during litigation and investigations in various sectors globally |
1,856 | |||
| 12 |
Navigantguidehouse.com
Global provider of management technology and risk consulting services helping public and commercial clients address transformational change technology innovation and regulatory pressure |
1,505 | |||
| 13 |
Tropicana Brands Grouptropicanabrandsgroup.com
manages a global portfolio of iconic juice brands, focusing on innovation, manufacturing, distribution, sales, marketing, and nutrition expertise |
1,253 | |||
| 14 |
A. M. Castle & Co.amcastle.com
Global supplier and processor of specialty metals serving aerospace, defense, industrial, and medical markets with quality and reliability. |
861 | |||
| 15 |
Revantage, A Blackstone Portfolio Companyrevantage.com
A global leader in corporate services catering to Blackstone Real Estate portfolio companies and investments worldwide |
666 | |||
| 16 |
International Equipment Solutionsindustrialtoolsandattachments.com
A global engineered equipment company focused on providing strong value propositions, outstanding customer service, and long-term growth strategies across domestic and international markets |
559 | |||
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. | |||||
| 17 |
Equity Office Propertiesequityoffice.com
Private equity-owned portfolio of premier office buildings in major US markets, managing assets for investor returns and customer satisfaction Headquarters in Chicago |
497 | |||
| 18 |
Experityexperityhealth.com
A leading software company for on-demand healthcare in the US urgent care market, offering integrated solutions to streamline operations and optimize revenue |
474 | |||
| 19 |
PPC Flexppcflex.com
Leader in cleanroom and consumer packaging for various industries, specializing in printed, laminated, and stand up pouch designs with exceptional speed to market and quality service |
424 | |||
| 20 |
SDI Presencesdipresence.com
IT consultancy and managed services provider offering strategic services, IT consulting, and hybrid multicloud infrastructure solutions to optimize technology environments for various industries |
411 | |||
| 21 |
Northstar Aerospacensaero.com
Leading manufacturer of aerospace components and assemblies, specializing in gears, transmissions, and rotorcraft drive systems Also provides maintenance and repair services |
361 | |||
| 22 |
SmartSource Technical Solutionsservicepoint.com
SmartSource offers IT staffing, multi-site deployment, technical solutions, and international services to businesses, VARs, OEMs, and global partners worldwide |
313 | |||
| 23 |
LivCor, a Blackstone Portfolio Companylivcor.com
A real estate company specializing in multi-family housing with a portfolio of over 400 properties totaling more than 150,000 units across the United States |
290 | |||
| 24 |
GoodVetsgoodvets.com
GoodVets is a veterinary care platform partnering with veterinarians to operate state-of-the-art facilities and provide exceptional healthcare for pets |
267 | |||
| 25 |
Valutech Outsourcingreconext.com
Valutech has merged with Reconext Follow Reconext for updates on the latest developments in technology and solutions |
263 | |||
| 26 |
Valto Engineered Materialscranecomposites.com
A world-leading provider of fiber-reinforced composite materials, specializing in innovative, lightweight products that outperform traditional metals and woods since 1954 |
261 | |||
| 27 |
Renaissancerenaissanceins.com
Specializing in innovative technology and services, we help insurance agencies achieve organic and profitable growth |
255 | |||
| 28 |
Iconstratusunlimited.com
A leading brand implementation company formed from a merger, focused on making a positive impact for clients and the world |
246 | |||
| 29 |
Buske Logisticsbuske.com
A global logistics company providing best-in-class services to fortune 500 clients in the US, Canada, and Mexico, with a focus on personal attention and cutting-edge technology |
227 | |||
| 30 |
Kensingkensingsolutions.com
The company specializes in producing premium quality sterols, natural vitamin E, anionic surfactants, and esters using pure ingredients while focusing on sustainability and innovation |
216 | |||
| 31 |
1WorldSync Content Solutions, by Syndigo1worldsync.com
A leading provider of product content solutions, enabling global companies to share trusted information, empowering intelligent purchase decisions through a technology platform |
103 | |||
| 32 |
GlobalViewenverus.com
A leading energy industry data and software company offering innovative technologies, predictive analytics, and collaborative solutions to global customers |
39 | |||
| 33 | 6 | ||||
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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 Nov 15, 2026.
More company lists in Illinois
- The largest companies in Illinois 4,685
- Multinational companies in Illinois 830
- Manufacturers in Illinois 528
- Education providers in Illinois 370
- Financial services firms in Illinois 352
- Professional services firms in Illinois 339
- Companies with in-house R&D in Illinois 322
- Hardware manufacturers in Illinois 296
- IT Services and IT Consulting companies in Illinois 294
- Hospitals and Health Care companies in Illinois 280
- IT services companies in Illinois 274
- Healthcare providers in Illinois 262
- Retail chains in Illinois 260
- Financial Services companies in Illinois 248
- Critical infrastructure operators in Illinois 241
- Consulting firms in Illinois 238
- Logistics companies in Illinois 228
- Transportation, Logistics, Supply Chain and Storage companies in Illinois 215
- SaaS companies in Illinois 182
- Companies with a mobile app in Illinois 178
- Family-owned companies in Illinois 166
- Subscription businesses in Illinois 160
- Corporate groups and holding companies in Illinois 154
- Publicly traded companies in Illinois 154
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 Massachusetts 29
- Private equity-backed companies in North Carolina 25
- Private equity-backed companies in New York 39