# Top 99 companies with in-house R&D in California

Tamtam tracks 1,276 companies with in-house R&D headquartered in California. This list ranks the 99 largest by number of employees on LinkedIn, led by Google, The Walt Disney Company and Apple. Their median headcount is 16,886. Half of them were founded in 1982 or later. The most common headquarters are San Francisco (12), San Jose (12) and Santa Clara (9).

These large California-based companies with in-house R&D are primarily focused on software development, technology, and internet services, alongside significant players in entertainment and healthcare. Key examples include Google, known for its search engine and web services; Apple, which designs and manufactures consumer electronics; The Walt Disney Company, an entertainment provider; and Kaiser Permanente, a not-for-profit health plan. The list also features Meta, focused on social technology platforms, and Uber, a global platform for transportation and delivery services.A notable pattern in this data is the concentration of headquarters in the San Francisco Bay Area. Cities like Mountain View, Cupertino, Menlo Park, and San Francisco itself host a significant number of these large R&D-driven enterprises. This indicates a strong regional hub for technological innovation and corporate research and development within California.

🇺🇸 California · 99 companies · Updated Nov 11, 2026

| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [Google](https://www.tamtam.ai/c/google) (google.com)<br>Provides a powerful search engine, web services, and advertising tools to help users find information and businesses reach customers | Software Development | 🇺🇸 Mountain View | 304,428 |  |
| 2 | [The Walt Disney Company](https://www.tamtam.ai/c/the-walt-disney-company) (thewaltdisneycompany.com)<br>An entertainment company creating magical experiences through animated features, theme park attractions, sports coverage, and television shows for global audiences | Entertainment Providers | 🇺🇸 Burbank | 220,000 |  |
| 3 | [Apple](https://www.tamtam.ai/c/apple) (apple.com)<br>Designs and manufactures innovative consumer electronics, including iPhones, iPads, and Macs, known for their user-friendly interfaces and sleek design | Computers and Electronics Manufacturing | 🇺🇸 Cupertino | 184,384 | 1976 |
| 4 | [Meta](https://www.tamtam.ai/c/meta) (meta.com)<br>Focuses on creating social technology platforms, including virtual and augmented reality experiences, and operates popular apps like Facebook and Instagram to connect people globally | Software Development | 🇺🇸 Menlo Park | 164,418 |  |
| 5 | [Uber](https://www.tamtam.ai/c/uber-san-francisco) (uber.com)<br>Global platform powering flexible earnings and movement of people and things, constantly reimagining how to enable transportation and delivery services worldwide | Internet Marketplace Platforms | 🇺🇸 San Francisco | 160,913 |  |
| 6 | [University of California](https://www.tamtam.ai/c/university-of-california) (jobs.universityofcalifornia.edu)<br>Educating top minds, advancing research, engaging communities, supporting economy, improving health, protecting environment, and driving innovation across California. | Higher Education | 🇺🇸 Oakland | 152,503 |  |
| 7 | [HP](https://www.tamtam.ai/c/hp) (hp.com)<br>This company creates technology solutions aiming to inspire innovation and make extraordinary contributions to humanity through climate action, human rights, and digital equity | IT Services and IT Consulting | 🇺🇸 Palo Alto | 142,944 |  |
| 8 | [Kaiser Permanente](https://www.tamtam.ai/c/kaiser-permanente) (healthy.kaiserpermanente.org)<br>Leading not-for-profit health plan with a unique business model driving industry improvements, serving millions of members across multiple states and impacting communities positively | Hospitals and Health Care | 🇺🇸 Oakland | 137,397 | 1945 |
| 9 | [YouTube](https://www.tamtam.ai/c/youtube) (youtube.com)<br>Team-oriented, creative workplace within Google, developing and rolling out key features and products quickly Headquartered in San Bruno Opportunities globally | Technology, Information and Internet | 🇺🇸 San Bruno | 113,401 |  |
| 10 | [Intel](https://www.tamtam.ai/c/intel) (intel.com)<br>This company drives innovation in AI, analytics, and cloud-to-edge technology to shape a better future through breakthroughs in self-driving cars, environmental conservation, and daily conveniences | Semiconductor Manufacturing | 🇺🇸 Santa Clara | 109,404 |  |
| 11 | [Cisco](https://www.tamtam.ai/c/cisco) (cisco.com)<br>A technology company founded in 1984, specializing in hardware, software, and services for Internet solutions and networking technologies | Software Development | 🇺🇸 San Jose | 95,899 | 1984 |
| 12 | [TikTok](https://www.tamtam.ai/c/tiktok) (tiktok.com)<br>A leading platform for short-form video, fostering creativity and innovation with a flat company structure and global presence for career growth opportunities | Entertainment Providers | 🇺🇸 Los Angeles | 91,370 |  |
| 13 | [Salesforce](https://www.tamtam.ai/c/salesforce) (salesforce.com)<br>It provides customer relationship management solutions, integrating data, artificial intelligence, and a focus on trust to enhance customer experiences. | Software Development | 🇺🇸 San Francisco | 86,347 |  |
| 14 | [DoorDash](https://www.tamtam.ai/c/doordash) (careersatdoordash.com)<br>A tech and logistics company focused on empowering local economies through delivery services, with a mission to expand beyond food delivery | Software Development | 🇺🇸 San Francisco | 80,754 |  |
| 15 | [Airbnb](https://www.tamtam.ai/c/airbnb) (airbnb.com)<br>The company offers unique stays and experiences worldwide through a platform connecting hosts with guests, fostering community connections | Software Development | 🇺🇸 San Francisco | 72,938 | 2007 |
| 16 | [Qualcomm](https://www.tamtam.ai/c/qualcomm) (qualcomm.com)<br>Providing widespread intelligent computing solutions | Semiconductor Manufacturing | 🇺🇸 San Diego | 57,548 |  |
| 17 | [Broadcom](https://www.tamtam.ai/c/broadcom) (broadcom.com)<br>A leading global infrastructure technology company with a rich history of innovation, collaboration, and engineering excellence spanning over 60 years | Semiconductor Manufacturing | 🇺🇸 Palo Alto | 54,926 |  |
| 18 | [NVIDIA](https://www.tamtam.ai/c/nvidia) (nvidia.com)<br>A pioneering company in accelerated computing, known for inventing the GPU, shaping PC gaming, computer graphics, AI development, and creating the metaverse | Computer Hardware Manufacturing | 🇺🇸 Santa Clara | 48,336 | 1993 |
| 19 | [AMD](https://www.tamtam.ai/c/amd) (amd.com)<br>A company focused on transforming lives with AMD technology through innovative products for data centers, AI, PCs, gaming, and embedded systems | Semiconductor Manufacturing | 🇺🇸 Santa Clara | 47,988 | 1969 |
| 20 | [Adobe](https://www.tamtam.ai/c/adobe) (adobe.com)<br>It provides digital media and marketing solutions, enabling users to create and deliver engaging experiences for various audiences effectively. | Software Development | 🇺🇸 San Jose | 42,354 | 1982 |
| 21 | [Amgen](https://www.tamtam.ai/c/amgen) (amgen.com)<br>This biotechnology company focuses on discovering and developing innovative therapeutics to improve health outcomes for patients with serious illnesses worldwide | Biotechnology Research | 🇺🇸 Thousand Oaks | 40,813 | 1980 |
| 22 | [Mattel, Inc.](https://www.tamtam.ai/c/mattel-inc) (mattel.com)<br>A purpose-driven company creating innovative products and experiences to inspire, entertain, and develop children through play, with iconic brands and global presence | Manufacturing | 🇺🇸 El Segundo | 37,000 | 1945 |
| 23 | [GlobalLogic](https://www.tamtam.ai/c/globallogic) (globallogic.com)<br>A global product development services leader, combining software engineering expertise and industry experience to help customers design and deliver next-generation products and digital experiences | Software Development | 🇺🇸 Santa Clara | 35,494 |  |
| 24 | [ServiceNow](https://www.tamtam.ai/c/servicenow) (servicenow.com)<br>Cloud-based platform digitizes and unifies organizations to streamline work processes, connect employees and customers, and enable innovation and agility Creating a smarter future | Software Development | 🇺🇸 Santa Clara | 35,136 |  |
| 25 | [Applied Materials](https://www.tamtam.ai/c/applied-materials) (appliedmaterials.com)<br>Leader in materials engineering solutions essential for semiconductor and advanced display technologies, enabling AI advancement and next-generation chip commercialization. | Semiconductor Manufacturing | 🇺🇸 Santa Clara | 31,512 | 1967 |
| 26 | [Visa](https://www.tamtam.ai/c/visa) (visa.com)<br>A global leader in digital payments, connecting consumers, merchants, and financial institutions across 200+ countries with secure transaction solutions | IT Services and IT Consulting | 🇺🇸 Foster City | 30,900 |  |
| 27 | [Stanford University](https://www.tamtam.ai/c/stanford-university) (stanford.edu)<br>Leading research university fostering innovation, education, and global citizenship with extensive resources, diverse programs, and strong community partnerships. | Higher Education | 🇺🇸 Stanford | 28,573 |  |
| 28 | [Synopsys Inc](https://www.tamtam.ai/c/synopsys-inc) (synopsys.com)<br>It provides comprehensive silicon and systems design solutions, partnering with customers to enhance R&D capabilities and drive innovation across industries. | Software Development | 🇺🇸 Sunnyvale | 27,809 |  |
| 29 | [eBay](https://www.tamtam.ai/c/ebay) (ebay.com)<br>This company creates pathways to connect millions of sellers and buyers globally, empowering customers to grow and thrive with innovative technology | Technology, Information and Internet | 🇺🇸 San Jose | 27,000 |  |
| 30 | [Experian](https://www.tamtam.ai/c/experian) (experianplc.com)<br>Global information services company empowering consumers and clients to manage data confidently, make smarter decisions, prevent fraud, and maximize opportunities worldwide | Information Services | 🇺🇸 Costa Mesa | 26,255 | 1980 |
| 31 | [Workday](https://www.tamtam.ai/c/workday) (workday.com)<br>Unifying human resources and finance on an AI-powered platform for high-impact outcomes through superintelligence, putting AI agents to work for people. | Software Development | 🇺🇸 Pleasanton | 25,233 | 2005 |
| 32 | [Agilent Technologies](https://www.tamtam.ai/c/agilent-technologies) (agilent.com)<br>Innovative company providing advanced analytical, research, and diagnostic solutions for various industries worldwide, including healthcare, environmental safety, and energy solutions | Biotechnology Research | 🇺🇸 Santa Clara | 25,000 | 1999 |
| 33 | [University of California, Berkeley](https://www.tamtam.ai/c/university-of-california-berkeley) (berkeley.edu)<br>Public research university offering diverse academic programs, fostering innovation, and serving as a flagship institution in California. | Higher Education | 🇺🇸 Berkeley | 24,082 | 1868 |
| 34 | [University of Southern California](https://www.tamtam.ai/c/university-of-southern-california) (usc.edu)<br>A leading private research university located in Los Angeles, focused on academic excellence and fostering a community of alumni and students | Higher Education | 🇺🇸 Los Angeles | 23,894 | 1880 |
| 35 | [Electronic Arts (EA)](https://www.tamtam.ai/c/electronic-arts-ea) (ea.com)<br>Develops and publishes interactive entertainment and video games, fostering a global community with creativity and player engagement. | Entertainment Providers | 🇺🇸 Redwood City | 23,703 |  |
| 36 | [LinkedIn](https://www.tamtam.ai/c/linkedin) (careers.linkedin.com)<br>It connects professionals globally, offering services like Talent Solutions, Marketing Solutions, Sales Solutions, and Premium Subscriptions for productivity and success. | Software Development | 🇺🇸 Sunnyvale | 23,635 |  |
| 37 | [Sanmina](https://www.tamtam.ai/c/sanmina) (sanmina.com)<br>A leading integrated manufacturing solutions provider offering end-to-end services to OEMs in various industries worldwide | Appliances, Electrical, and Electronics Manufacturing | 🇺🇸 San Jose | 22,931 | 1980 |
| 38 | [WD](https://www.tamtam.ai/c/wd) (westerndigital.com)<br>This company creates innovative data storage solutions for current technology and future advancements | Computer Hardware Manufacturing | 🇺🇸 San Jose | 22,696 | 1970 |
| 39 | [Palo Alto Networks](https://www.tamtam.ai/c/palo-alto-networks) (paloaltonetworks.com)<br>A global cybersecurity leader addressing security challenges through continuous innovation with artificial intelligence, analytics, automation, and orchestration for organizations worldwide | Computer and Network Security | 🇺🇸 Santa Clara | 22,680 | 2005 |
| 40 | [University of California, Davis](https://www.tamtam.ai/c/university-of-california-davis) (ucdavis.edu)<br>Public university offering diverse undergraduate and graduate programs, conducting extensive research, fostering innovation, and preparing future leaders across multiple disciplines. | Higher Education | 🇺🇸 Davis | 21,439 | 1908 |
| 41 | [SpaceX](https://www.tamtam.ai/c/spacex) (spacex.com)<br>A company specializing in designing, manufacturing, and launching advanced rockets and spacecraft with a goal of making life multiplanetary | Aviation and Aerospace Component Manufacturing | 🇺🇸 Hawthorne | 20,008 | 2002 |
| 42 | [Netflix](https://www.tamtam.ai/c/netflix) (netflix.com)<br>A global entertainment service offering a wide range of TV shows, movies, and games in multiple genres and languages for millions of paid members worldwide | Entertainment Providers | 🇺🇸 Los Gatos | 18,533 | 1997 |
| 43 | [Genentech](https://www.tamtam.ai/c/genentech) (gene.com)<br>A cutting-edge science company passionate about finding innovative solutions for difficult-to-treat conditions, providing global access to life-changing medicines | Biotechnology Research | 🇺🇸 South San Francisco | 18,287 | 1976 |
| 44 | [Intuit](https://www.tamtam.ai/c/intuit) (intuit.com)<br>A global technology platform helping customers overcome financial challenges, providing solutions like TurboTax, QuickBooks, Credit Karma, and Mailchimp | Software Development | 🇺🇸 Mountain View | 18,222 | 1983 |
| 45 | [Broadcom Software](https://www.tamtam.ai/c/broadcom-software) (broadcom.com)<br>Global software leader optimizing and protecting complex hybrid environments for multinational companies with industry-leading business-critical software, enabling scalability, agility, and security | Software Development | 🇺🇸 San Jose | 17,981 |  |
| 46 | [UCLA Health](https://www.tamtam.ai/c/ucla-health) (uclahealth.org)<br>Comprehensive healthcare system with top-ranked hospitals, advanced medical technology, expert physicians, and pioneering biomedical research across multiple specialties. | Hospitals and Health Care | 🇺🇸 Los Angeles | 17,812 | 1955 |
| 47 | [Rodan + Fields](https://www.tamtam.ai/c/rodan-fields) (rodanandfields.com)<br>A skincare company founded by dermatologists focusing on giving people the best skin and confidence, with a commitment to social impact | Manufacturing | 🇺🇸 San Francisco | 17,749 | 2000 |
| 48 | [Levi Strauss & Co.](https://www.tamtam.ai/c/levi-strauss-and-co) (levistrauss.com)<br>designs and markets iconic denim jeans and apparel brands, emphasizing sustainability, innovation, and global self-expression through fashion. | Retail Apparel and Fashion | 🇺🇸 San Francisco | 17,743 | 1853 |
| 49 | [Lam Research](https://www.tamtam.ai/c/lam-research) (lamresearch.com)<br>Design and manufacture advanced equipment that enables semiconductor chipmakers to innovate and drive technological progress across various industries. | Semiconductor Manufacturing | 🇺🇸 Fremont | 17,202 | 1980 |
| 50 | [KLA](https://www.tamtam.ai/c/kla) (kla.com)<br>Developing industry-leading equipment and services for the electronics industry, KLA provides advanced process control solutions for manufacturing various electronic components in collaboration with global customers | Semiconductor Manufacturing | 🇺🇸 Milpitas | 16,886 |  |
| 51 | [Cedars-Sinai](https://www.tamtam.ai/c/cedars-sinai) (careers.cshs.org)<br>Comprehensive healthcare provider excelling in patient care, pioneering research, advanced medical education, and community health improvement in Los Angeles. | Hospitals and Health Care | 🇺🇸 Los Angeles | 16,865 |  |
| 52 | [Seagate Technology](https://www.tamtam.ai/c/seagate-technology) (seagate.com)<br>Leading provider of scalable mass-capacity data storage solutions, ensuring trust and integrity for innovations relying on vast data volumes. | Computer Hardware Manufacturing | 🇺🇸 Fremont | 16,700 | 1979 |
| 53 | [Fortinet](https://www.tamtam.ai/c/fortinet) (fortinet.com)<br>Fortinet enables trust in the digital world by protecting people, devices, and data for enterprises, service providers, and government organizations | Computer and Network Security | 🇺🇸 Sunnyvale | 16,304 | 2000 |
| 54 | [Skechers](https://www.tamtam.ai/c/skechers) (careers.skechers.com)<br>A global brand that creates stylish, comfortable, and innovative footwear, apparel, and accessories for men, women, and children at affordable prices | Retail | 🇺🇸 Manhattan Beach | 16,264 |  |
| 55 | [Stripe](https://www.tamtam.ai/c/stripe) (stripe.com)<br>Financial infrastructure platform enabling businesses to accept payments, increase revenue, and explore new opportunities to grow in San Francisco and Dublin | Technology, Information and Internet | 🇺🇸 South San Francisco | 16,031 | 2010 |
| 56 | [Databricks](https://www.tamtam.ai/c/databricks) (databricks.com)<br>It provides a Data Intelligence Platform for organizations to manage their data effectively and leverage AI for better decision-making. | Software Development | 🇺🇸 San Francisco | 15,896 |  |
| 57 | [Williams-Sonoma, Inc.](https://www.tamtam.ai/c/williams-sonoma-inc) (williams-sonomainc.com)<br>Specialty retailer offering high-quality kitchenware, furniture, and home decor through brands like Pottery Barn and West Elm across global multi-channel retail platforms. | Retail | 🇺🇸 San Francisco | 15,546 |  |
| 58 | [Autodesk](https://www.tamtam.ai/c/autodesk) (autodesk.com)<br>It provides software for architecture, engineering, construction, and media, enabling users to design, collaborate, and solve various challenges effectively. | Software Development | 🇺🇸 San Francisco | 15,378 | 1982 |
| 59 | [Stanford Health Care](https://www.tamtam.ai/c/stanford-health-care) (stanfordhealthcare.org)<br>Providing advanced, coordinated care in multiple specialties including cancer, neurosciences, cardiovascular, surgery, and organ transplant with innovative research and compassionate treatment. | Hospitals and Health Care | 🇺🇸 Palo Alto | 15,318 | 1885 |
| 60 | [Herbalife](https://www.tamtam.ai/c/herbalife-los-angeles) (herbalife.com)<br>Global health and wellness company offering nutrition products, coaching support, and business opportunities to empower personal growth and community impact. | Wellness and Fitness Services | 🇺🇸 Los Angeles | 15,172 | 1980 |
| 61 | [American Honda Motor Company, Inc.](https://www.tamtam.ai/c/american-honda-motor-company-inc) (honda.com)<br>Design and manufacture cars, trucks, advanced light jets, and mobility solutions focused on enhancing life potential and environmental responsibility. | Motor Vehicle Manufacturing | 🇺🇸 Torrance | 15,103 |  |
| 62 | [Gilead Sciences](https://www.tamtam.ai/c/gilead-sciences) (gilead.com)<br>A company focused on delivering innovative medicines in virology and oncology, addressing health inequities, and empowering people to live healthier lives | Biotechnology Research | 🇺🇸 Foster City | 14,891 | 1987 |
| 63 | [Equinix](https://www.tamtam.ai/c/equinix) (equinix.com)<br>A global digital infrastructure company empowering businesses to access foundational infrastructure, partners, and possibilities to accelerate advantage and multiply value | IT Services and IT Consulting | 🇺🇸 Redwood City | 14,710 | 1998 |
| 64 | [UC Irvine](https://www.tamtam.ai/c/uc-irvine) (uci.edu)<br>A top public research university in Southern California committed to rigorous academics, cutting-edge research, and leadership development with global impact | Higher Education | 🇺🇸 Irvine | 14,695 | 1965 |
| 65 | [Edwards Lifesciences](https://www.tamtam.ai/c/edwards-lifesciences) (edwards.com)<br>Develops breakthrough structural heart technologies and medical devices for patients, partnering with clinicians to improve lives globally across over 100 countries. | Medical Equipment Manufacturing | 🇺🇸 Irvine | 14,148 | 1958 |
| 66 | [Keysight Technologies](https://www.tamtam.ai/c/keysight-technologies) (keysight.com)<br>Empowers innovators to explore, design, and bring world-changing technologies to life by solving design, emulation, and test challenges to help create the best product experiences | Appliances, Electrical, and Electronics Manufacturing | 🇺🇸 Santa Rosa | 13,893 |  |
| 67 | [Pinterest](https://www.tamtam.ai/c/pinterest) (pinterest.com)<br>It is a visual inspiration platform with 482 million monthly active users, helping people search, save, and shop ideas. | Software Development | 🇺🇸 San Francisco | 13,766 | 2010 |
| 68 | [Intuitive](https://www.tamtam.ai/c/intuitive-sacramento) (intuitive.com)<br>A global technology leader in minimally invasive care and robotic-assisted surgery, utilizing intelligent technology to enhance patient outcomes without constraints | Medical Equipment Manufacturing | 🇺🇸 California | 13,240 | 1995 |
| 69 | [Sony Interactive Entertainment](https://www.tamtam.ai/c/sony-interactive-entertainment) (sonyinteractive.com)<br>A global leader in entertainment and innovation, delivering cutting-edge hardware, network services, and award-winning games through the PlayStation line of products | Entertainment Providers | 🇺🇸 San Mateo | 13,000 |  |
| 70 | [Symantec](https://www.tamtam.ai/c/symantec) (broadcom.com)<br>It offers comprehensive cybersecurity solutions for Endpoint, Network, Data, and Cloud security, catering to both individuals and enterprises. | Software Development | 🇺🇸 San Jose | 12,852 | 1982 |
| 71 | [NetApp](https://www.tamtam.ai/c/netapp) (netapp.com)<br>It builds intelligent data infrastructure, enabling applications to utilize any data from anywhere, enhancing data management and accessibility. | Software Development | 🇺🇸 San Jose | 12,680 | 1992 |
| 72 | [City of Hope](https://www.tamtam.ai/c/city-of-hope) (cityofhope.org)<br>Comprehensive cancer research, treatment, and innovation with a national network, focusing on breakthrough medicines and patient care integration. | Hospitals and Health Care | 🇺🇸 Duarte | 12,442 | 1913 |
| 73 | [Block](https://www.tamtam.ai/c/block-oakland) (block.xyz)<br>Block is a company dedicated to economic empowerment, with diverse teams providing support in areas such as people, finance, legal, and security | Financial Services | 🇺🇸 Oakland | 12,038 |  |
| 74 | [Rivian](https://www.tamtam.ai/c/rivian) (careers.rivian.com)<br>Innovative team dedicated to challenging conventional thinking and seeking new solutions to protect the outdoors for future generations | Motor Vehicle Manufacturing | 🇺🇸 Irvine | 11,979 | 2009 |
| 75 | [Marvell Technology](https://www.tamtam.ai/c/marvell-technology) (marvell.com)<br>Specializing in infrastructure technology, we collaborate closely with clients to deliver tailored solutions, leveraging innovation and partnership to drive progress and success | Semiconductor Manufacturing | 🇺🇸 Santa Clara | 11,815 | 1995 |
| 76 | [\[24\]7.ai](https://www.tamtam.ai/c/24-7-ai) (247.ai)<br>This company provides customer engagement solutions using conversational AI to create personalized, predictive, and effortless customer experiences across all channels | Software Development | 🇺🇸 Campbell | 11,656 | 2000 |
| 77 | [Cadence](https://www.tamtam.ai/c/cadence) (cadence.com)<br>Development of software, hardware, and IP enabling innovative electronic product design across diverse markets like 5G, automotive, aerospace, and healthcare. | Software Development | 🇺🇸 San Jose | 11,424 | 1988 |
| 78 | [VMware](https://www.tamtam.ai/c/vmware) (broadcom.com)<br>Leading provider of multi-cloud services enabling digital innovation with enterprise control Cultivating innovation to solve customer challenges with disruptive technologies | Software Development | 🇺🇸 Palo Alto | 11,230 |  |
| 79 | [General Atomics](https://www.tamtam.ai/c/general-atomics) (ga.com)<br>Development of advanced technology solutions including unmanned aerial vehicles, research reactors, aircraft systems, MagLev transport, and fusion energy for global customers. | Defense and Space Manufacturing | 🇺🇸 San Diego | 11,213 |  |
| 80 | [UC San Diego Health](https://www.tamtam.ai/c/uc-san-diego-health) (employment.ucsd.edu)<br>A leading academic health system in San Diego region, offering outstanding patient care, cutting-edge research, medical education, and community health programs | Hospitals and Health Care | 🇺🇸 San Diego | 10,962 | 1966 |
| 81 | [Beckman Coulter Diagnostics](https://www.tamtam.ai/c/beckman-coulter-diagnostics) (beckmancoulter.com)<br>Develops and provides advanced diagnostic solutions for complex clinical testing in hospitals, reference laboratories, and physician offices to improve patient health. | Medical Equipment Manufacturing | 🇺🇸 Brea | 10,628 | 1935 |
| 82 | [UC Santa Barbara](https://www.tamtam.ai/c/uc-santa-barbara) (ucsb.edu)<br>A renowned institution on the California coast, UCSB fosters academic excellence and creativity, showcasing achievements and connecting the Gaucho community | Higher Education | 🇺🇸 Santa Barbara | 10,619 |  |
| 83 | [Veeva Systems](https://www.tamtam.ai/c/veeva-systems) (veeva.com)<br>Cloud-based software solutions for global life sciences industry, serving pharmaceutical companies and biotechs with innovation and customer success. | Software Development | 🇺🇸 Pleasanton | 10,036 | 2007 |
| 84 | [Roblox](https://www.tamtam.ai/c/roblox) (careers.roblox.com)<br>A platform where millions of creators build immersive virtual experiences for people to connect, learn, work, play, and socialize together | Software Development | 🇺🇸 San Mateo | 9,978 | 2004 |
| 85 | [Nutanix](https://www.tamtam.ai/c/nutanix) (nutanix.com)<br>Global leader in cloud software, providing a platform for running apps and data across clouds, simplifying operations for businesses worldwide | Software Development | 🇺🇸 San Jose | 9,917 |  |
| 86 | [Teradata](https://www.tamtam.ai/c/teradata) (teradata.com)<br>The company specializes in providing a cloud analytics and data platform that empowers organizations with harmonized data and trusted AI/ML for confident decision-making and impactful results | Software Development | 🇺🇸 San Diego | 9,882 | 1979 |
| 87 | [Deel](https://www.tamtam.ai/c/deel) (deel.com)<br>Platform offering HR tools, payroll, compliance, and mobility services to help companies manage and scale international workforces efficiently. | Human Resources Services | 🇺🇸 San Francisco | 9,873 | 2019 |
| 88 | [University of California, Santa Cruz](https://www.tamtam.ai/c/university-of-california-santa-cruz) (ucsc.edu)<br>A pioneering university with a focus on social justice, groundbreaking research, and a unique academic environment, producing influential alumni worldwide | Higher Education | 🇺🇸 Santa Cruz | 9,767 | 1965 |
| 89 | [Illumina](https://www.tamtam.ai/c/illumina) (illumina.com)<br>The company develops innovative technologies and assays for genetic analysis, enabling personalized medicine and advancing disease research, drug development, and molecular testing | Biotechnology Research | 🇺🇸 San Diego | 9,673 | 1998 |
| 90 | [UC Davis Health](https://www.tamtam.ai/c/uc-davis-health) (health.ucdavis.edu)<br>Academic health system with top medical school, hospital, research centers, nursing school, and community partnerships advancing patient care and health innovation. | Hospitals and Health Care | 🇺🇸 Sacramento | 9,647 | 1968 |
| 91 | [Lawrence Livermore National Laboratory](https://www.tamtam.ai/c/lawrence-livermore-national-laboratory) (llnl.gov)<br>Development and application of advanced science, technology, and engineering to enhance national security, counterterrorism, defense, energy, and environmental challenges. | Research Services | 🇺🇸 Livermore | 9,546 | 1952 |
| 92 | [Bio-Rad Laboratories](https://www.tamtam.ai/c/bio-rad-laboratories) (bio-rad.com)<br>Development and supply of innovative products for life science research and medical diagnostics, enhancing discovery and clinical results worldwide. | Biotechnology Research | 🇺🇸 Hercules | 9,416 | 1952 |
| 93 | [Stanford University School of Medicine](https://www.tamtam.ai/c/stanford-university-school-of-medicine) (med.stanford.edu)<br>Premier academic hub combining research, education, and clinical care to advance health through innovation, leadership, and collaborative discoveries. | Higher Education | 🇺🇸 Palo Alto | 9,384 |  |
| 94 | [Logitech](https://www.tamtam.ai/c/logitech) (logitech.com)<br>Innovative hardware and software solutions bringing people together in work, creation, gaming, and streaming, with a focus on sustainability | Computers and Electronics Manufacturing | 🇺🇸 San Jose | 9,325 | 1981 |
| 95 | [OpenAI](https://www.tamtam.ai/c/openai) (openai.com)<br>An AI research and deployment company focused on creating safe and beneficial general-purpose artificial intelligence for the benefit of humanity | Research Services | 🇺🇸 San Francisco | 9,268 | 2015 |
| 96 | [ICU Medical](https://www.tamtam.ai/c/icu-medical) (icumed.com)<br>Specializes in safe, innovative IV therapy products, smart pumps, software, and consumables designed to improve patient care and safety. | Medical Equipment Manufacturing | 🇺🇸 San Clemente | 9,144 |  |
| 97 | [Juniper Networks](https://www.tamtam.ai/c/juniper-networks) (juniper.net)<br>Develops intelligent, agile, and secure networking products and solutions serving global service providers, enterprises, and government organizations worldwide. | Software Development | 🇺🇸 Sunnyvale | 9,059 | 1996 |
| 98 | [Dexcom](https://www.tamtam.ai/c/dexcom) (dexcom.com)<br>A leader in continuous glucose monitoring technology, empowering individuals with diabetes to control their health and pursue their dreams | Medical Equipment Manufacturing | 🇺🇸 San Diego | 8,997 | 1999 |
| 99 | [Zscaler](https://www.tamtam.ai/c/zscaler) (zscaler.com)<br>Leading organization enabling secure network and application transformation for mobile and cloud-first world, offering fast, secure, cloud-delivered services globally for enhanced cybersecurity | Computer and Network Security | 🇺🇸 San Jose | 8,865 | 2007 |

## 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 California

- [The largest companies in California](https://www.tamtam.ai/l/largest-companies-california) (15,265)
- [Multinational companies in California](https://www.tamtam.ai/l/multinational-companies-california) (2,592)
- [SaaS companies in California](https://www.tamtam.ai/l/saas-companies-california) (1,855)
- [Software Development companies in California](https://www.tamtam.ai/l/software-development-companies-california) (1,650)
- [AI companies in California](https://www.tamtam.ai/l/ai-companies-california) (1,297)
- [Manufacturers in California](https://www.tamtam.ai/l/manufacturers-california) (1,066)
- [Hardware manufacturers in California](https://www.tamtam.ai/l/hardware-companies-california) (985)
- [IT Services and IT Consulting companies in California](https://www.tamtam.ai/l/it-services-and-it-consulting-companies-california) (968)
- [Education providers in California](https://www.tamtam.ai/l/education-companies-california-united-states) (950)
- [Subscription businesses in California](https://www.tamtam.ai/l/subscription-businesses-california) (940)
- [Venture capital and private equity firms in California](https://www.tamtam.ai/l/vc-and-private-equity-firms-california) (917)
- [Professional services firms in California](https://www.tamtam.ai/l/professional-services-firms-california) (880)
- [Companies with a mobile app in California](https://www.tamtam.ai/l/companies-with-mobile-app-california) (827)
- [Retail chains in California](https://www.tamtam.ai/l/retail-chains-california) (803)
- [IT services companies in California](https://www.tamtam.ai/l/it-services-companies-california) (796)
- [Venture Capital and Private Equity Principals companies in California](https://www.tamtam.ai/l/venture-capital-and-private-equity-principals-companies-california) (731)
- [Financial services firms in California](https://www.tamtam.ai/l/financial-services-firms-california) (711)
- [Financial Services companies in California](https://www.tamtam.ai/l/financial-services-companies-california) (642)
- [Healthcare providers in California](https://www.tamtam.ai/l/healthcare-providers-california) (569)
- [AI-native companies in California](https://www.tamtam.ai/l/ai-native-companies-california) (561)
- [Hospitals and Health Care companies in California](https://www.tamtam.ai/l/hospitals-and-health-care-companies-california) (555)
- [Consulting firms in California](https://www.tamtam.ai/l/consulting-firms-california) (551)
- [Public sector organisations in California](https://www.tamtam.ai/l/public-sector-organisations-california) (535)
- [Technology, Information and Internet companies in California](https://www.tamtam.ai/l/technology-information-and-internet-companies-california) (514)

## 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 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 Illinois](https://www.tamtam.ai/l/r-and-d-companies-illinois) (322)
- [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-california