# Top 100 companies with in-house R&D in Illinois

Tamtam tracks 322 companies with in-house R&D headquartered in Illinois. This list ranks the 100 largest by number of employees on LinkedIn, led by McDonald's, Abbott and JLL. Their median headcount is 3,043. Half of them were founded in 1932 or later. The most common headquarters are Chicago (43), Lisle (4) and Deerfield (3).

These Illinois-based companies with in-house R&D are primarily large, established firms across diverse sectors. They include global leaders such as McDonald's, the fast-food chain, Abbott, a healthcare technology provider, and JLL, a real estate and investment management firm. Other prominent companies are Mondelēz International, known for snack brands like Oreo, and John Deere, a leader in agriculture and construction machinery.

A clear pattern among these organizations is the strong presence of the food and beverage manufacturing sector, with companies like ADM and Kraft Heinz alongside Mondelēz. Another notable concentration is in medical and pharmaceutical fields, represented by Abbott, AbbVie, GE HealthCare, and Baxter International, reflecting a significant investment in health-related innovation within the state.

🇺🇸 Illinois · 100 companies · Updated Nov 11, 2026

| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [McDonald's](https://www.tamtam.ai/c/mcdonald-s) (corporate.mcdonalds.com)<br>global fast-food restaurant chain operating over 37,000 locations worldwide, serving popular menu items and employing 1.9 million people | Restaurants | 🇺🇸 Chicago | 261,219 |  |
| 2 | [Abbott](https://www.tamtam.ai/c/abbott-abbott-park) (abbott.com)<br>A global healthcare leader offering life-changing technologies in diagnostics, medical devices, nutrition, and generic medicines, with over 115,000 colleagues serving in 160+ countries | Hospitals and Health Care | 🇺🇸 Abbott Park | 140,778 |  |
| 3 | [JLL](https://www.tamtam.ai/c/jll) (jill.com)<br>A leading professional services firm specializing in real estate and investment management, creating rewarding opportunities and sustainable solutions using advanced technology | Real Estate | 🇺🇸 Chicago | 104,899 |  |
| 4 | [Mondelēz International](https://www.tamtam.ai/c/mondelez-international) (mondelezinternational.com)<br>Global multinational manufacturing and marketing iconic snacks, biscuits, chocolate, candy, and gum brands including Oreo and Cadbury to empower people to snack right. | Food and Beverage Manufacturing | 🇺🇸 Chicago | 79,000 | 2012 |
| 5 | [AbbVie](https://www.tamtam.ai/c/abbvie) (abbvie.com)<br>Global biopharmaceutical company focused on creating impactful medicines for complex health issues in immunology, oncology, neuroscience, eye care, aesthetics, and other unmet needs | Pharmaceutical Manufacturing | 🇺🇸 North Chicago | 61,015 |  |
| 6 | [GE HealthCare](https://www.tamtam.ai/c/ge-healthcare) (gehealthcare.com)<br>Global medical technology and digital solutions innovator leveraging intelligent devices, data analytics, and artificial intelligence to drive precision health and improve patient outcomes worldwide | Hospitals and Health Care | 🇺🇸 Chicago | 60,041 | 1892 |
| 7 | [John Deere](https://www.tamtam.ai/c/john-deere) (deere.com)<br>A global leader in cutting-edge products and technology for agriculture and construction, pushing boundaries for productivity and sustainability worldwide | Machinery Manufacturing | 🇺🇸 Moline | 55,618 | 1837 |
| 8 | [ADM](https://www.tamtam.ai/c/adm) (adm.com)<br>Global nutrition company transforming industries with plant-based solutions, sustainable practices, and cutting-edge innovations for a healthier, more environmentally friendly future | Food and Beverage Manufacturing | 🇺🇸 Chicago | 42,789 | 1902 |
| 9 | [Baxter International Inc.](https://www.tamtam.ai/c/baxter-international-inc) (baxter.com)<br>Development and delivery of innovative medical technologies and solutions to support clinicians and improve patient health worldwide. | Medical Equipment Manufacturing | 🇺🇸 Deerfield | 39,170 |  |
| 10 | [Kraft Heinz](https://www.tamtam.ai/c/kraft-heinz) (kraftheinz.com)<br>Producer of high-quality food and beverage products including condiments, dairy, meals, beverages, and nutrition items marketed worldwide. | Food and Beverage Services | 🇺🇸 Chicago | 39,000 | 2015 |
| 11 | [Motorola Solutions](https://www.tamtam.ai/c/motorola-solutions) (motorolasolutions.com)<br>The company builds and connects technologies to enhance public safety collaboration for safer communities, schools, hospitals, and businesses worldwide | Telecommunications | 🇺🇸 Chicago | 28,153 |  |
| 12 | [University of Illinois Urbana-Champaign](https://www.tamtam.ai/c/university-of-illinois-urbana-champaign) (illinois.edu)<br>Leading public university with strong focus on education, research, global student opportunities, faculty innovation, and significant economic and community impact. | Higher Education | 🇺🇸 Champaign | 24,692 |  |
| 13 | [ITW](https://www.tamtam.ai/c/itw) (careers.itw.com)<br>Global multi-industrial manufacturing leader driving solid growth with innovative solutions, emphasizing decentralized culture | Machinery Manufacturing | 🇺🇸 Glenview | 18,709 | 1912 |
| 14 | [University of Chicago](https://www.tamtam.ai/c/university-of-chicago) (uchicago.edu)<br>A prestigious academic institution encouraging scholars and students to think critically, explore various disciplines, and challenge conventional ideas for global enrichment | Higher Education | 🇺🇸 Chicago | 18,526 |  |
| 15 | [Motorola Mobility (a Lenovo Company)](https://www.tamtam.ai/c/motorola-mobility-a-lenovo-company) (motorola.com)<br>Innovative smartphones and accessories are created by a global team, fostering collaboration, creativity, and a commitment to consumer-centric mobile technology innovation | Computers and Electronics Manufacturing | 🇺🇸 Chicago | 17,456 | 1928 |
| 16 | [TransUnion](https://www.tamtam.ai/c/transunion) (transunion.com)<br>Global information and insights company enabling trust and confident transactions by providing actionable, data-driven pictures of individuals for businesses and consumers worldwide | IT Services and IT Consulting | 🇺🇸 Chicago | 17,036 |  |
| 17 | [Molex](https://www.tamtam.ai/c/molex) (molex.com)<br>Global company providing connectivity solutions for various industries, including data communications, medical, automotive, and consumer electronics, to improve lives and transform the future | Appliances, Electrical, and Electronics Manufacturing | 🇺🇸 Lisle | 14,810 | 1938 |
| 18 | [UL Solutions](https://www.tamtam.ai/c/ul-solutions) (ul.com)<br>Global provider of safety testing, certification, inspection, auditing, and advisory services ensuring product security, sustainability, and market trust. | Professional Services | 🇺🇸 Northbrook | 14,487 | 1894 |
| 19 | [Nalco Water, An Ecolab Company](https://www.tamtam.ai/c/nalco-water-an-ecolab-company) (ecolab.com)<br>A global leader in water and process management solutions, leveraging connected chemistry and digital innovation to optimize sustainability and business outcomes | Chemical Manufacturing | 🇺🇸 Naperville | 12,751 |  |
| 20 | [Rush University Medical Center](https://www.tamtam.ai/c/rush-university-medical-center) (rush.edu)<br>Academic medical center with hospital, health center, university offering medical, nursing education, research, residency programs, and community outreach services. | Hospitals and Health Care | 🇺🇸 Chicago | 12,484 |  |
| 21 | [Zebra Technologies](https://www.tamtam.ai/c/zebra-technologies) (zebra.com)<br>Improving workflows through innovative technology solutions, connecting frontline workers and optimizing visibility with scanning, track-and-trace, and automation tools | IT Services and IT Consulting | 🇺🇸 Lincolnshire | 11,698 |  |
| 22 | [Advocate Health Care](https://www.tamtam.ai/c/advocate-health-care) (advocatehealth.com)<br>Integrated nonprofit health system providing clinical innovation, specialized care, extensive research, education, and community benefits across multiple U.S. states. | Hospitals and Health Care | 🇺🇸 Oak Brook | 11,676 |  |
| 23 | [International](https://www.tamtam.ai/c/international) (international.com)<br>Manufacture durable trucks, engines, and buses with aftermarket parts, focusing on uptime, productivity, and sustainable mobility solutions. | Motor Vehicle Manufacturing | 🇺🇸 Lisle | 10,420 |  |
| 24 | [Brunswick Corporation](https://www.tamtam.ai/c/brunswick-corporation) (brunswick.com)<br>Global leader in marine recreation offering propulsion systems, boats, marine technology, parts, accessories, and related services worldwide. | Manufacturing | 🇺🇸 Mettawa | 9,409 |  |
| 25 | [Aptar](https://www.tamtam.ai/c/aptar) (aptar.com)<br>Global leader in drug and consumer product dosing, dispensing and protection technologies, creating innovative solutions for various end markets and brands. | Packaging and Containers Manufacturing | 🇺🇸 | 7,968 |  |
| 26 | [Conagra Brands](https://www.tamtam.ai/c/conagra-brands) (conagrabrands.com)<br>Diverse team managing iconic and emerging food brands with a focus on innovation, integrity, and consistent business results. | Food and Beverage Services | 🇺🇸 Chicago | 7,846 | 1919 |
| 27 | [Northwestern Memorial Hospital](https://www.tamtam.ai/c/northwestern-memorial-hospital) (nmh.org)<br>A collaboration between healthcare and university partners, Northwestern Medicine aims to transform healthcare through research, teaching, and patient care excellence | Hospitals and Health Care | 🇺🇸 Chicago | 7,371 |  |
| 28 | [Ann & Robert H. Lurie Children's Hospital of Chicago](https://www.tamtam.ai/c/ann-and-robert-h-lurie-children-s-hospital-of-chicago) (luriechildrens.org)<br>Largest pediatric healthcare provider in the region, teaching partner of Northwestern University, nationally ranked in all pediatric specialties. | Hospitals and Health Care | 🇺🇸 Chicago | 7,202 |  |
| 29 | [Paylocity](https://www.tamtam.ai/c/paylocity) (paylocity.com)<br>Award-winning provider of cloud-based HR and payroll software solutions, helping businesses automate processes, attract talent, and build employee connections | Software Development | 🇺🇸 Schaumburg | 7,046 | 1997 |
| 30 | [Navistar Inc](https://www.tamtam.ai/c/navistar-inc) (international.com)<br>Manufacturing and selling commercial trucks, focusing on heavy-duty vehicles and returning to the International brand identity. | Motor Vehicle Manufacturing | 🇺🇸 Lisle | 6,795 | 1902 |
| 31 | [Dover Corporation](https://www.tamtam.ai/c/dover-corporation) (dovercorporation.com)<br>A global manufacturer and solutions provider delivering innovative equipment, components, and digital solutions across various industries with operational agility and entrepreneurial approach | Machinery Manufacturing | 🇺🇸 Downers Grove | 6,338 |  |
| 32 | [Kellanova](https://www.tamtam.ai/c/kellanova) (kellanova.com)<br>A global powerhouse in snacks, cereal, noodles, and frozen foods, committed to creating better days and promoting sustainable access to food | Food and Beverage Manufacturing | 🇺🇸 Chicago | 6,197 | 2023 |
| 33 | [Flex-N-Gate](https://www.tamtam.ai/c/flex-n-gate) (flex-n-gate.com)<br>A leading provider of high-quality automotive products and systems, specializing in aftermarket and OEM parts with a focus on continuous improvement and on-time delivery | Motor Vehicle Manufacturing | 🇺🇸 Urbana | 6,096 | 1956 |
| 34 | [NorthShore University HealthSystem](https://www.tamtam.ai/c/northshore-university-healthsystem) (endeavorhealth.org)<br>Integrated health system delivering personal patient care, convenient access, and pioneering medical services across multiple hospitals and clinics in Illinois. | Hospitals and Health Care | 🇺🇸 Evanston | 5,857 |  |
| 35 | [USG](https://www.tamtam.ai/c/usg) (usg.com)<br>A leading manufacturer of building products, providing innovative solutions for walls, ceilings, flooring, and roofing in construction markets worldwide | Wholesale Building Materials | 🇺🇸 Chicago | 5,752 | 1902 |
| 36 | [Ferrara](https://www.tamtam.ai/c/ferrara) (ferrarausa.com)<br>A leading sugar confectionery company in the US, focused on driving category development with a diverse portfolio of iconic brands | Food and Beverage Manufacturing | 🇺🇸 Chicago | 5,430 | 1908 |
| 37 | [Littelfuse](https://www.tamtam.ai/c/littelfuse) (littelfuse.com)<br>A global industrial technology manufacturing company providing innovative solutions for industrial, transportation, and electronics markets with a commitment to diversity and equal employment opportunities | Appliances, Electrical, and Electronics Manufacturing | 🇺🇸 Rosemont | 5,181 | 1927 |
| 38 | [James Hardie](https://www.tamtam.ai/c/james-hardie) (jameshardie.com)<br>Global leader in high-performance fiber cement and fiber gypsum building solutions, empowering homeowners and professionals worldwide with premium quality products for design and protection | Wholesale Building Materials | 🇺🇸 Chicago | 5,022 |  |
| 39 | [Panduit](https://www.tamtam.ai/c/panduit) (panduit.com)<br>The company provides innovative electrical and network infrastructure solutions, serving as a trusted advisor in Data Center, Enterprise, and Industrial environments | Appliances, Electrical, and Electronics Manufacturing | 🇺🇸 Tinley Park | 4,640 | 1955 |
| 40 | [Northwestern University - The Feinberg School of Medicine](https://www.tamtam.ai/c/northwestern-university-the-feinberg-school-of-medicine) (feinberg.northwestern.edu)<br>A renowned medical school in Chicago offering MD programs, research, patient care, and community service to educate future physicians | Higher Education | 🇺🇸 Chicago | 4,009 | 1859 |
| 41 | [CTS Corporation](https://www.tamtam.ai/c/cts-corporation) (ctscorp.com)<br>Design and manufacture sensors, actuators, and electronic components for OEMs across diverse industries, focusing on innovative, quality technology solutions. | Manufacturing | 🇺🇸 Lisle | 3,953 |  |
| 42 | [Videojet Technologies](https://www.tamtam.ai/c/videojet-technologies) (videojet.com)<br>Global leader in coding and marking equipment, offering CIJ printers, laser marking systems, TTO printers, LPA, TIJ printers, and innovative track and trace solutions | Printing Services | 🇺🇸 Wood Dale | 3,815 |  |
| 43 | [Hollister Incorporated](https://www.tamtam.ai/c/hollister-incorporated) (hollister.com)<br>develops, manufactures, and markets healthcare products and services globally, aiming to make life more rewarding and dignified for users through dignity, integrity, service, and stewardship. | Medical Equipment Manufacturing | 🇺🇸 Libertyville | 3,755 | 1921 |
| 44 | [Amsted Industries](https://www.tamtam.ai/c/amsted-industries) (amsted.com)<br>Global manufacturer of industrial components for railroad, automotive, commercial vehicle, construction, and building markets, with a focus on innovation and employee ownership | Industrial Machinery Manufacturing | 🇺🇸 Chicago | 3,554 |  |
| 45 | [Griffith Foods](https://www.tamtam.ai/c/griffith-foods) (griffithfoods.com)<br>Global food company specializing in creative product development, partnering with customers to meet consumer needs while respecting the planet. | Food and Beverage Manufacturing | 🇺🇸 Alsip | 3,448 | 1919 |
| 46 | [Midwestern University](https://www.tamtam.ai/c/midwestern-university) (midwestern.edu)<br>Not-for-profit graduate institution offering health science degrees including medicine, pharmacy, therapy, psychology, nursing, dentistry, optometry, and veterinary medicine | Higher Education | 🇺🇸 Downers Grove | 3,419 | 1900 |
| 47 | [IDEX Corporation](https://www.tamtam.ai/c/idex-corporation) (idexcorp.com)<br>The company manufactures mission-critical components used in everyday activities such as automotive safety, emergency rescue tools, and medical equipment | Manufacturing | 🇺🇸 Northbrook | 3,315 |  |
| 48 | [NAV Fund Services](https://www.tamtam.ai/c/nav-fund-services) (navfundservices.com)<br>Top-ranked fund administrator with award-winning service and technology, specializing in cost-effective solutions, digital assets, and emerging managers | Financial Services | 🇺🇸 Oakbrook Terrace | 3,061 | 1991 |
| 49 | [Tempus AI](https://www.tamtam.ai/c/tempus-ai) (tempus.com)<br>Utilizing AI and data analytics, the company empowers physicians to personalize patient care with real-time insights and targeted therapies | Biotechnology Research | 🇺🇸 Chicago | 3,051 | 2015 |
| 50 | [Methode Electronics](https://www.tamtam.ai/c/methode-electronics) (methode.com)<br>Designs, engineers, produces mechatronic products for OEMs, utilizing broad technologies for user interface, LED lighting, power distribution, and sensor applications. | Appliances, Electrical, and Electronics Manufacturing | 🇺🇸 Chicago | 3,043 |  |
| 51 | [JBT Marel](https://www.tamtam.ai/c/jbt-marel) (jbtmarel.com)<br>Provider of integrated technology, equipment, software, and services for food and beverage industries, supporting diverse product sectors worldwide. | Machinery Manufacturing | 🇺🇸 Chicago | 2,852 | 1884 |
| 52 | [Applied Systems](https://www.tamtam.ai/c/applied-systems) (www1.appliedsystems.com)<br>A leading provider of innovative cloud software for the insurance industry, driving transformation through digitization, automation, and new partnerships | Software Development | 🇺🇸 Chicago | 2,813 | 1983 |
| 53 | [UI Health](https://www.tamtam.ai/c/ui-health) (hospital.uillinois.edu)<br>This academic health enterprise in Illinois offers comprehensive care, education, and research to promote health equity and train healthcare leaders | Hospitals and Health Care | 🇺🇸 Chicago | 2,813 |  |
| 54 | [Chamberlain Group](https://www.tamtam.ai/c/chamberlain-group) (chamberlaingroup.com)<br>A global leader in intelligent access technology, providing seamless, secure access to homes and businesses through innovative products and software solutions | Software Development | 🇺🇸 Oak Brook | 2,781 | 1954 |
| 55 | [S&C Electric Company](https://www.tamtam.ai/c/s-and-c-electric-company) (sandc.com)<br>This company specializes in developing innovative solutions for a more intelligent and resilient electrical grid, aiming for an outage-free, sustainable energy future | Electrical Equipment Manufacturing | 🇺🇸 Chicago | 2,761 | 1911 |
| 56 | [North American Lighting, Inc.](https://www.tamtam.ai/c/north-american-lighting-inc) (nal.com)<br>Largest Tier-1 automotive exterior lighting supplier in North America, provides lamp assemblies to automotive manufacturers, including Toyota, Honda, Nissan, Ford, Subaru, and General Motors. | Motor Vehicle Manufacturing | 🇺🇸 Paris | 2,737 | 1983 |
| 57 | [Fortune Brands Innovations](https://www.tamtam.ai/c/fortune-brands-innovations) (fbin.com)<br>Designs and manufactures water innovations, outdoor living products, security solutions, and kitchen and bath cabinets for homeowners. | Manufacturing | 🇺🇸 Deerfield | 2,603 |  |
| 58 | [GE Transportation, a Wabtec company](https://www.tamtam.ai/c/ge-transportation-a-wabtec-company) (wabteccorp.com)<br>A global leader in digital industrial solutions for rail, mining, marine, power, and drilling industries, specializing in advanced manufacturing and connected machines | Truck Transportation | 🇺🇸 Chicago | 2,533 | 1907 |
| 59 | [Robert Bosch Tool Corporation NA](https://www.tamtam.ai/c/robert-bosch-tool-corporation-na) (boschtools.com)<br>Industry-leading tool corporation manufacturing power tools and accessories, providing innovative, durable, and versatile products through diverse global opportunities for growth and development | Manufacturing | 🇺🇸 Mt. Prospect | 2,525 | 1886 |
| 60 | [DRW](https://www.tamtam.ai/c/drw) (drw.com)<br>Global principal trading firm capturing investment opportunities through technology and research across multiple asset classes while maintaining a collaborative, high-performance culture for employees. | Financial Services | 🇺🇸 Chicago | 2,463 |  |
| 61 | [University of Illinois System](https://www.tamtam.ai/c/university-of-illinois-system) (uillinois.edu)<br>The company is a flagship public university system in Illinois, offering excellence in education, healthcare, research, and economic development to the community | Higher Education | 🇺🇸 Urbana-Champaign | 2,436 |  |
| 62 | [Gardner Denver](https://www.tamtam.ai/c/gardner-denver) (gardnerdenver.com)<br>Manufacturing energy efficient, reliable, and IoT connected compressors, blowers, and vacuum products for diverse industrial applications and processes. | Machinery Manufacturing | 🇺🇸 Quincy | 2,384 |  |
| 63 | [Shure](https://www.tamtam.ai/c/shure) (shure.com)<br>Designs and manufactures wired and wireless microphones, networked audio systems, signal processors, conferencing systems, and premium earphones and headphones. | Computers and Electronics Manufacturing | 🇺🇸 Niles | 2,320 | 1925 |
| 64 | [Omron Automation](https://www.tamtam.ai/c/omron-automation) (automation.omron.com)<br>The company specializes in automation technology to enhance performance, efficiency, and safety for manufacturing and infrastructure industries worldwide | Automation Machinery Manufacturing | 🇺🇸 Hoffman Estates | 2,300 | 1933 |
| 65 | [Life Fitness / Hammer Strength](https://www.tamtam.ai/c/life-fitness-hammer-strength) (lifefitness.com)<br>A global leader in fitness solutions for over 45 years, inspiring healthier lives through cardio, strength, group training, and rehabilitation products | Wellness and Fitness Services | 🇺🇸 Rosemont | 2,264 |  |
| 66 | [Hendrickson](https://www.tamtam.ai/c/hendrickson) (hendrickson-intl.com)<br>The company specializes in designing and manufacturing high-quality truck, tractor, and trailer suspensions, steel leaf springs, bumpers, and stamped components for the heavy-duty transportation market worldwide | Truck Transportation | 🇺🇸 Woodridge | 2,247 | 1913 |
| 67 | [Moen](https://www.tamtam.ai/c/moen) (moen.com)<br>Designing and engineering innovative water products focused on enhancing user experience while promoting water conservation and efficiency. | Wholesale Building Materials | 🇺🇸 Deerfield | 2,211 |  |
| 68 | [Stepan Company](https://www.tamtam.ai/c/stepan-company) (stepan.com)<br>A global manufacturer of specialty chemical products, Stepan collaborates with customers to provide innovative, high-quality solutions for various markets worldwide | Chemical Manufacturing | 🇺🇸 Northbrook | 2,210 | 1932 |
| 69 | [Knowles Corporation](https://www.tamtam.ai/c/knowles-corporation) (knowles.com)<br>Designs and manufactures specialty electronic components like capacitors, RF filters, microphones, and balanced armatures for MedTech, Defense, and Industrial markets. | Appliances, Electrical, and Electronics Manufacturing | 🇺🇸 Itasca | 2,150 | 1946 |
| 70 | [Shirley Ryan AbilityLab](https://www.tamtam.ai/c/shirley-ryan-abilitylab) (sralab.org)<br>Specializes in treating severe physical disabilities through integrated clinical care and research, improving recovery for complex conditions. | Hospitals and Health Care | 🇺🇸 Chicago | 2,124 | 1954 |
| 71 | [Newly Weds Foods](https://www.tamtam.ai/c/newly-weds-foods) (newlywedsfoods.com)<br>A global leader in food ingredient innovation, specializing in customized food coatings, seasonings, and sauces, with manufacturing facilities worldwide | Food and Beverage Manufacturing | 🇺🇸 Chicago | 2,123 | 1932 |
| 72 | [Flexera](https://www.tamtam.ai/c/flexera) (flexera.com)<br>Provides comprehensive visibility and actionable insights on entire IT ecosystems, enabling organizations to optimize spend, mitigate risk, and achieve positive business outcomes. | Software Development | 🇺🇸 Itasca | 2,096 | 2008 |
| 73 | [Wilson Sporting Goods Co.](https://www.tamtam.ai/c/wilson-sporting-goods-co) (wilson.com)<br>A leading manufacturer of high-performance sports equipment, apparel, and accessories, committed to helping athletes worldwide reach their true potential through innovative products | Sporting Goods Manufacturing | 🇺🇸 Chicago | 1,929 | 1914 |
| 74 | [Northwest Community Healthcare](https://www.tamtam.ai/c/northwest-community-healthcare) (endeavorhealth.org)<br>Endeavor Health is a united healthcare system providing personalized patient experiences and world-class care through convenient access and collaboration #OurEndeavor | Hospitals and Health Care | 🇺🇸 Arlington Heights | 1,916 |  |
| 75 | [Relativity](https://www.tamtam.ai/c/relativity) (relativity.com)<br>A software company offering RelativityOne, a SaaS product for data organization, truth discovery, and action during litigation and investigations in various sectors globally | Software Development | 🇺🇸 Chicago | 1,856 |  |
| 76 | [Fresenius Kabi USA](https://www.tamtam.ai/c/fresenius-kabi-usa) (fresenius-kabi.com)<br>A global healthcare company specializing in Pharma, Nutrition, MedTech, and BioPharma products for critical and chronic conditions worldwide | Pharmaceutical Manufacturing | 🇺🇸 Lake Zurich | 1,759 |  |
| 77 | [Alere Inc.](https://www.tamtam.ai/c/alere-inc) (globalpointofcare.abbott)<br>A global healthcare leader offering life-changing technologies in diagnostics, medical devices, nutritionals, and branded generic medicines with a presence in over 160 countries | Medical Equipment Manufacturing | 🇺🇸 North Chicago | 1,757 | 1981 |
| 78 | [Robertshaw](https://www.tamtam.ai/c/robertshaw) (robertshaw.com)<br>Global engineering and manufacturing company specializing in product solutions for the white goods industry, with a diverse portfolio of controls for appliances | Appliances, Electrical, and Electronics Manufacturing | 🇺🇸 Itasca | 1,742 | 1899 |
| 79 | [Pregis](https://www.tamtam.ai/c/pregis) (pregis.com)<br>Global provider of protective packaging materials and systems for consumer and industrial markets, with a focus on sustainability and innovation | Packaging and Containers Manufacturing | 🇺🇸 Chicago | 1,682 | 1997 |
| 80 | [SRAM](https://www.tamtam.ai/c/sram) (sram.com)<br>Design and manufacture bicycle components such as shifters, derailleurs, brakes, chains, suspension, and power meters for global markets. | Manufacturing | 🇺🇸 Chicago | 1,608 | 1987 |
| 81 | [OSI Group](https://www.tamtam.ai/c/osi-group) (osigroup.com)<br>Custom value-added food product development, global sourcing, processing, and distribution for leading foodservice and retail brands worldwide. | Food and Beverage Manufacturing | 🇺🇸 Aurora | 1,601 | 1909 |
| 82 | [American Dental Association](https://www.tamtam.ai/c/american-dental-association) (ada.org)<br>Advocates for dentists, dental science, public oral health. Provides resources for professionals, researches, and champions public health initiatives. | Non-profit Organizations | 🇺🇸 Chicago | 1,599 | 1859 |
| 83 | [Enova International](https://www.tamtam.ai/c/enova-international) (enova.com)<br>A financial services company offering online lending to small businesses and underserved consumers, providing over $52 billion in loans | Financial Services | 🇺🇸 Chicago | 1,570 | 2004 |
| 84 | [Inventus Power](https://www.tamtam.ai/c/inventus-power) (inventuspower.com)<br>Design and manufacture advanced Li-ion battery packs, smart chargers, and power supplies for global OEMs across portable, motive, and stationary applications. | Appliances, Electrical, and Electronics Manufacturing | 🇺🇸 Woodridge | 1,564 | 1960 |
| 85 | [Basis](https://www.tamtam.ai/c/basis) (basis.com)<br>Global provider of media automation and programmatic advertising software, streamlining and unifying digital campaigns through a centralized platform Headquarters in Chicago with strong workplace culture | Technology, Information and Media | 🇺🇸 Chicago | 1,477 |  |
| 86 | [Navico Group](https://www.tamtam.ai/c/navico-group) (navico.com)<br>Leading supplier of integrated systems in marine, recreational vehicle, and other industries Brands include marine electronics, power management, and digital control products | Manufacturing | 🇺🇸 Mettawa | 1,427 |  |
| 87 | [Filtration Group](https://www.tamtam.ai/c/filtration-group) (filtrationgroup.com)<br>Global provider of innovative filtration consumables serving diverse industries including process technologies, life sciences, and specialty technologies worldwide. | Manufacturing | 🇺🇸 Oakbrook Terrace | 1,413 |  |
| 88 | [JBT FoodTech](https://www.tamtam.ai/c/jbt-foodtech) (jbtc.com)<br>Design, manufacture, and service customized industrial equipment for processing meat, seafood, poultry, bakery, dairy, juice, and packaged foods worldwide. | Machinery Manufacturing | 🇺🇸 Chicago | 1,407 |  |
| 89 | [JBT Corporation](https://www.tamtam.ai/c/jbt-corporation) (jbtc.com)<br>Global technology solutions provider for food and beverage industry, specializing in processing equipment and automated guided vehicle systems for various applications | Machinery Manufacturing | 🇺🇸 Chicago | 1,380 | 1884 |
| 90 | [Wahl Clipper Corporation](https://www.tamtam.ai/c/wahl-clipper-corporation) (wahl.com)<br>This company makes and markets electric hair clippers, massagers, beard trimmers, and accessories for professional, home, and animal use, selling globally through retailers and subsidiaries. | Manufacturing | 🇺🇸 Sterling | 1,054 | 1919 |
| 91 | [FUCHS LUBRICANTS CO.](https://www.tamtam.ai/c/fuchs-lubricants-co) (fuchs.com)<br>Global leader in specialty lubricants, offering innovative products for various industries worldwide, with a focus on quality, innovation, and customer service | Chemical Manufacturing | 🇺🇸 Harvey | 1,349 | 1931 |
| 92 | [INX International Ink Co.](https://www.tamtam.ai/c/inx-international-ink-co) (inxinternational.com)<br>A leading ink and coating supplier specializing in printing formulations for various applications, offering customizable solutions with a strong focus on digital printing integration | Chemical Manufacturing | 🇺🇸 Schaumburg | 1,332 | 1992 |
| 93 | [EPS](https://www.tamtam.ai/c/eps-marengo) (epscca.com)<br>This company provides high performance resins and colorants for coatings and adhesives industries, with a focus on customer success and innovation | Chemical Manufacturing | 🇺🇸 Marengo | 1,332 |  |
| 94 | [Mérieux NutriSciences - North America](https://www.tamtam.ai/c/merieux-nutrisciences-north-america) (mxns.com)<br>Global food safety partner providing testing, labeling, auditing, consulting, and research services to the food industry worldwide, focusing on consumer health and scientific excellence | Biotechnology Research | 🇺🇸 Chicago | 1,301 | 1967 |
| 95 | [iManage](https://www.tamtam.ai/c/imanage) (imanage.com)<br>The company provides an intelligent, cloud-enabled knowledge work platform using AI to uncover and activate organizational content for informed decisions and collaboration | Software Development | 🇺🇸 Chicago | 1,276 | 2015 |
| 96 | [Voyant Beauty](https://www.tamtam.ai/c/voyant-beauty) (voyantbeauty.com)<br>This company specializes in developing and manufacturing high-performance personal care and beauty products, offering marketing insights, ingredient research, and award-winning products | Personal Care Product Manufacturing | 🇺🇸 Hodgkins | 1,260 | 1989 |
| 97 | [Tropicana Brands Group](https://www.tamtam.ai/c/tropicana-brands-group) (tropicanabrandsgroup.com)<br>manages a global portfolio of iconic juice brands, focusing on innovation, manufacturing, distribution, sales, marketing, and nutrition expertise | Food and Beverage Services | 🇺🇸 Chicago | 1,253 | 2022 |
| 98 | [MAT Holdings, Inc.](https://www.tamtam.ai/c/mat-holdings-inc) (matholdingsinc.com)<br>Engineering and manufacturing automotive castings, friction parts, suspension components, and consumer products like fencing, tools, and outdoor equipment. | Motor Vehicle Manufacturing | 🇺🇸 Long Grove | 1,200 | 1984 |
| 99 | [Dynacast International](https://www.tamtam.ai/c/dynacast-international) (dynacast.com)<br>A global leader in high-quality die cast components for various industries, leveraging 80+ years of experience to deliver precision engineered metal components | Manufacturing | 🇺🇸 Elgin | 1,171 | 1936 |
| 100 | [Amsted Rail](https://www.tamtam.ai/c/amsted-rail) (amstedrail.com)<br>Global manufacturer providing components and systems for freight cars and locomotives, alongside repair services, track maintenance, and monitoring solutions for heavy haul transportation industry worldwide | Railroad Equipment Manufacturing | 🇺🇸 Chicago | 1,160 |  |

## 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 Illinois

- [The largest companies in Illinois](https://www.tamtam.ai/l/largest-companies-illinois) (4,687)
- [Multinational companies in Illinois](https://www.tamtam.ai/l/multinational-companies-illinois) (831)
- [Manufacturers in Illinois](https://www.tamtam.ai/l/manufacturers-illinois) (528)
- [Education providers in Illinois](https://www.tamtam.ai/l/education-companies-illinois) (370)
- [Financial services firms in Illinois](https://www.tamtam.ai/l/financial-services-firms-illinois) (352)
- [Professional services firms in Illinois](https://www.tamtam.ai/l/professional-services-firms-illinois) (339)
- [Hardware manufacturers in Illinois](https://www.tamtam.ai/l/hardware-companies-illinois) (296)
- [IT Services and IT Consulting companies in Illinois](https://www.tamtam.ai/l/it-services-and-it-consulting-companies-illinois) (294)
- [Hospitals and Health Care companies in Illinois](https://www.tamtam.ai/l/hospitals-and-health-care-companies-illinois) (280)
- [IT services companies in Illinois](https://www.tamtam.ai/l/it-services-companies-illinois) (274)
- [Healthcare providers in Illinois](https://www.tamtam.ai/l/healthcare-providers-illinois) (262)
- [Retail chains in Illinois](https://www.tamtam.ai/l/retail-chains-illinois) (260)
- [Financial Services companies in Illinois](https://www.tamtam.ai/l/financial-services-companies-illinois) (248)
- [Critical infrastructure operators in Illinois](https://www.tamtam.ai/l/critical-infrastructure-operators-illinois) (241)
- [Consulting firms in Illinois](https://www.tamtam.ai/l/consulting-firms-illinois) (238)
- [Logistics companies in Illinois](https://www.tamtam.ai/l/logistics-companies-illinois) (228)
- [Transportation, Logistics, Supply Chain and Storage companies in Illinois](https://www.tamtam.ai/l/transportation-logistics-supply-chain-and-storage-companies-illinois) (215)
- [SaaS companies in Illinois](https://www.tamtam.ai/l/saas-companies-illinois) (182)
- [Companies with a mobile app in Illinois](https://www.tamtam.ai/l/companies-with-mobile-app-illinois) (178)
- [Family-owned companies in Illinois](https://www.tamtam.ai/l/family-owned-companies-illinois) (166)
- [Subscription businesses in Illinois](https://www.tamtam.ai/l/subscription-businesses-illinois) (160)
- [Corporate groups and holding companies in Illinois](https://www.tamtam.ai/l/holding-companies-illinois) (154)
- [Publicly traded companies in Illinois](https://www.tamtam.ai/l/publicly-traded-companies-illinois) (154)
- [Public sector organisations in Illinois](https://www.tamtam.ai/l/public-sector-organisations-illinois) (147)

## The same list elsewhere in United States

- [Companies with in-house R&D in the United States](https://www.tamtam.ai/l/r-and-d-companies-united-states) (6,796)
- [Companies with in-house R&D in California](https://www.tamtam.ai/l/r-and-d-companies-california) (1,276)
- [Companies with in-house R&D in Texas](https://www.tamtam.ai/l/r-and-d-companies-texas) (442)
- [Companies with in-house R&D in New York State](https://www.tamtam.ai/l/r-and-d-companies-new-york-state) (419)
- [Companies with in-house R&D in Massachusetts](https://www.tamtam.ai/l/r-and-d-companies-massachusetts) (396)
- [Companies with in-house R&D in Michigan](https://www.tamtam.ai/l/r-and-d-companies-michigan) (287)
- [Companies with in-house R&D in Ohio](https://www.tamtam.ai/l/r-and-d-companies-ohio) (277)
- [Companies with in-house R&D in Pennsylvania](https://www.tamtam.ai/l/r-and-d-companies-pennsylvania) (255)
- [Companies with in-house R&D in New Jersey](https://www.tamtam.ai/l/r-and-d-companies-new-jersey) (224)
- [Companies with in-house R&D in Florida](https://www.tamtam.ai/l/r-and-d-companies-florida) (221)
- [Companies with in-house R&D in Alabama](https://www.tamtam.ai/l/r-and-d-companies-alabama) (214)
- [Companies with in-house R&D in Georgia](https://www.tamtam.ai/l/r-and-d-companies-georgia) (173)
- [Companies with in-house R&D in Virginia](https://www.tamtam.ai/l/r-and-d-companies-virginia) (166)
- [Companies with in-house R&D in North Carolina](https://www.tamtam.ai/l/r-and-d-companies-north-carolina) (158)
- [Companies with in-house R&D in Wisconsin](https://www.tamtam.ai/l/r-and-d-companies-wisconsin) (154)
- [Companies with in-house R&D in Minnesota](https://www.tamtam.ai/l/r-and-d-companies-minnesota) (146)
- [Companies with in-house R&D in Washington State](https://www.tamtam.ai/l/r-and-d-companies-washington-state) (140)
- [Companies with in-house R&D in Colorado](https://www.tamtam.ai/l/r-and-d-companies-colorado) (113)
- [Companies with in-house R&D in Maryland](https://www.tamtam.ai/l/r-and-d-companies-maryland) (107)
- [Companies with in-house R&D in Indiana](https://www.tamtam.ai/l/r-and-d-companies-indiana) (104)
- [Companies with in-house R&D in New York](https://www.tamtam.ai/l/r-and-d-companies-new-york) (223)
- [Companies with in-house R&D in San Francisco](https://www.tamtam.ai/l/r-and-d-companies-san-francisco) (147)
- [Companies with in-house R&D in Houston](https://www.tamtam.ai/l/r-and-d-companies-houston) (129)
- [Companies with in-house R&D in San Jose](https://www.tamtam.ai/l/r-and-d-companies-san-jose) (103)

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Source: https://www.tamtam.ai/l/r-and-d-companies-illinois