| # | Company | Employees |
|---|---|---|
| 1 |
Tetra Techtetratech.com
A global provider of consulting and engineering services, specializing in innovative technical solutions for water, environment, infrastructure, energy, and international development projects |
27,460 |
| 2 |
NASA Jet Propulsion Laboratoryjpl.jobs
A federally funded research and development center managed by Caltech for NASA, specializing in space exploration, technology development, and scientific problem-solving |
8,652 |
| 3 |
Caltechcaltech.edu
A leading science and engineering research institution in California focused on seeking answers, discovering new knowledge, and transforming the future |
5,794 |
| 4 |
Inter-Con Securityicsecurity.com
A multinational private security company providing comprehensive security services, risk analysis, and management to government agencies, businesses, and individuals globally |
5,126 |
| 5 |
East West Bankeastwestbank.com
Provides banking services connecting U.S. and Asia, supporting businesses in real estate, media, venture capital, and high-tech sectors. |
3,916 |
| 6 |
Total Safetytotalsafety.com
Provider of integrated safety services and products, including gas detection, respiratory protection, safety training, fire protection, and industrial hygiene |
3,336 |
| 7 |
San Jacinto Collegesanjac.edu
Provides college education, job-ready skills, and career pathways to students, fostering economic prosperity in the Greater Houston area through various academic and technical programs. |
3,092 |
| 8 |
ACCO Engineered Systemsaccoes.com
A leading mechanical contractor offering design, installation, maintenance, and service of HVAC, refrigeration, plumbing, process piping, and building automation systems |
2,686 |
| 9 |
Pasadena Independent School Districtpasadenaisd.org
Empowering students in a culturally rich community to become self-directed citizen-scholars through rigorous curriculum, innovative programs, and positive relationships |
2,646 |
| 10 |
Huntington Healthhuntingtonhealth.org
Affiliated with Cedars-Sinai, Huntington Health provides a wide range of healthcare services, including emergency care, surgery, cancer treatment, and maternity services |
2,581 |
| 11 |
Pasadena City Collegepasadena.edu
California Community College system member offering education and resources, accessible online or in person at the Office of Student Life in CC105 |
2,517 |
| 12 |
Dave's Hot Chickendaveshotchicken.com
A popular hot chicken restaurant started as a pop-up, now seeking multi-unit operators nationwide due to high demand |
2,466 |
| 13 |
Applebee's Neighborhood Grill + Barapplebees.com
Neighborhood grill and bar offering simple, craveable American fare with classic drinks. Franchised restaurants support local charities and employee growth. |
2,056 |
| 14 |
University of the Peopleuopeople.edu
A non-profit, tuition-free online university offering American accredited degrees, providing flexible and affordable education opportunities for students worldwide |
1,972 |
| 15 |
City of Pasadenacityofpasadena.net
Provides diverse municipal services including public safety, utilities, health, and transportation across sixteen departments with nineteen hundred employees for a historic California community. |
1,787 |
| 16 | 1,766 | |
| 17 |
Pinnaclepinnaclereliability.com
A company based in Pasadena, focused on helping industrial facilities in oil and gas, chemical, mining, and water industries optimize data for improved performance |
1,701 |
| 18 |
ArtCenter College of Designartcenter.edu
Provides rigorous, immersive curriculum in art and design education. Prepares next generation creative leaders, offering access to influencers and industry professionals. |
1,489 |
| 19 | 1,417 | |
| 20 |
Pasadena ISDvirtualschool.pasadenaisd.org
Online high school courses with well-developed curriculum aligned with district, state, and national standards for flexible and independent learning |
1,412 |
| 21 |
Wedbushwedbush.com
Provides brokerage, wealth management, and investment banking services to private and institutional clients. Focuses on client service, financial safety, innovation, and advanced technology. |
1,041 |
| 22 |
FutureCare Healthfuturecare.com
Family-owned healthcare organization in Baltimore that prioritizes staff growth and fulfillment, values input, and provides top-notch care for residents |
1,002 |
| 23 |
Pasadena Unified School Districtpusd.us
A school district in California serving 17,000 students, offering themed learning options and partnerships with civic, business, and higher education organizations |
996 |
| 24 |
Wetzel's Pretzels, LLCwetzels.com
This company specializes in baking unique and unconventional soft pretzels with ingredients like jalapenos, pepperoni, ham, cheese, and more |
964 |
| 25 |
Dine Brands Globaldinebrands.com
Established in 2007, this company owns and supports over 3,700 Applebee's and IHOP restaurants globally, focusing on growth, innovation, and collaboration |
869 |
| 26 |
IBEW Local 11ibew11.org
The company is a union for electrical workers focused on ensuring safety, fair wages, training programs, and benefits for its members |
850 |
| 27 |
Arrowhead Pharmaceuticalsarrowheadpharma.com
A clinical stage company developing RNAi-based therapies to treat intractable diseases by silencing target genes, offering potentially life-changing treatments |
799 |
| 28 |
Fuller Theological Seminaryfuller.edu
An evangelical graduate institution offering diverse degree programs to form global leaders for kingdom vocations, with a diverse student body and alumni network |
797 |
| 29 |
Bluebeambluebeam.com
Development of smart, simple digital solutions enhancing project communication, collaboration, and efficiency for design and construction professionals worldwide. |
726 |
| 30 |
Western Asset Managementwesternasset.com
Global fixed-income investment management firm offering long-term, research-driven strategies and risk management to deliver superior client returns worldwide. |
718 |
| 31 |
C.W. Driver Companiescwdriver.com
A premier builder in California since 1919, offering General Contracting, Construction Management, and Design-Build services for educational, civic, urban, and commercial projects |
643 |
| 32 |
Alexandria Real Estate Equities, Inc.are.com
Owner, operator, and developer of premier life science real estate campuses in major innovation clusters supporting health-focused tenants. |
638 |
| 33 |
Yard Houseyardhouse.com
Offering a wide selection of draft beers and a menu of freshly prepared dishes, giving customers a unique dining experience |
624 |
| 34 |
Polytechnic Schoolpolytechnic.org
A college-preparatory school from K-12 fostering academic excellence, responsibility, and service Emphasizes active learning, inquisitive students, passionate faculty, and supportive staff Alumni network available |
616 |
| 35 |
Options For Youth Public Charter Schoolsbit.ly
A non-profit network of charter high schools offering flexible, personalized education through diverse class formats and strong student-teacher relationships since 1987 |
590 |
| 36 |
LACERAlacera.gov
A leading retirement system for Los Angeles County employees and survivors, dedicated to providing promised benefits through innovative technology and investments |
562 |
| 37 |
Sun Pacificsunpacific.com
This company cultivates specialty crops on fertile California land to delight customers across North America and beyond, starting with orange groves |
533 |
| 38 | 526 | |
| 39 |
Pasadena Unified School Districtpusd.us
The company focuses on preparing students for success in education, careers, and life with the community's support, fostering excellence and meeting diverse needs |
492 |
| 40 |
Numeradenumerade.com
Virtual learning platform focused on STEM education, providing tools to promote understanding and relevance to learners |
467 |
| 41 | 467 | |
| 42 |
Kaiser Permanente Bernard J. Tyson School of Medicinemedschool.kp.org
The Kaiser Permanente Bernard J Tyson School of Medicine in Pasadena, California offers a diverse, innovative medical education program focusing on holistic patient care and lifelong learning |
459 |
| 43 |
Cogentthalesgroup.com
Cogent business, now part of Thales Group, specializes in digital identity and security solutions Visit Thales Digital Identity & Security for updates |
444 |
| 44 | 432 | |
| 45 |
Sunbelt Supplysunbeltsupply.com
Global provider of flow control solutions with extensive inventory of valves, actuators, and PFF Specializing in valve automation services and specialty piping products |
419 |
| 46 |
Firefighters First Credit Unionfirefightersfirstcu.org
A credit union providing specialized financial services to firefighters and their families since 1935, ensuring their financial well-being at work and home |
405 |
| 47 |
Guidance Softwaresecurity.opentext.com
Provides applications for digital investigations and endpoint data security, ensuring information safety and continuity for companies and their customers. Solutions deployed on millions of endpoints. |
405 |
| 48 |
Coffee Club
Coffee Club provides hospitality services in Pasadena, California, offering a warm and welcoming atmosphere for customers to enjoy coffee and socialize |
403 |
| 49 |
Hospice of the Chesapeakehospicechesapeake.org
Providing physical, emotional, and spiritual support services for individuals with advanced illness, as well as grief support for all community members |
384 |
| 50 |
Kaiser Permanente - Southern California Permanente Medical Group Physician Careerssoutherncalifornia.permanente.org
Delivering patient-centered, high-quality healthcare in America through a physician-led, innovative care delivery model supported by technology, education, and wellness programs |
383 |
| 51 |
Rusnak Auto Grouprusnakcars.com
A leader in luxury automotive retail with a diverse workforce, commitment to community, and focus on exceptional customer service and career development |
377 |
| 52 |
Dog Hausdoghaus.com
Craft-casual eatery known for gourmet hot dogs, sausages, smash burgers, shakes, and beer program featuring local brews Menu emphasizes quality, creativity, and community |
358 |
| 53 |
The Center for Connectionthecenterforconnection.org
A medical practice company based in Pasadena, CA, focused on enhancing human connection and well-being through personalized healthcare services |
352 |
| 54 |
Acuity Eye Groupacuityeyegroup.com
A leading network of ophthalmic clinics in the US, providing quality eye care through a team of skilled professionals across California |
334 |
| 55 | 333 | |
| 56 |
MEITEC Inc.meitec.net
A team of licensed professionals offering global electrical and instrumentation services for oil, gas, marine, and petrochemical industries for over 30 years |
324 |
| 57 |
Douglas Realty, LLCgodouglasrealty.com
A residential and commercial real estate brokerage providing support, technology, and efficient services to agents and clients, while actively supporting the community |
319 |
| 58 |
TechCorr USA, LLCtechcorr.com
TechCorr provides safe, high-quality inspection services worldwide, using advanced technology, certified Inspectors and Technicians for various industry needs |
319 |
| 59 |
BallerTVballertv.com
A sports network connecting families worldwide through live sports, founded in 2016 and based in Pasadena, California |
312 |
| 60 |
Xencorxencor.com
This company specializes in developing antibody and protein biotherapeutics using proprietary protein engineering technologies to improve patient outcomes and quality of life |
302 |
| 61 |
Supplyframesupplyframe.com
Harnessing billions of market signals for real-time insights across the design-to-market product lifecycle, informing professionals and optimizing direct materials spend. |
286 |
| 62 |
TradeSTAR, Inctradestarinc.com
A project staffing firm specializing in electrical & low voltage staffing, providing professional installers to contractors for local, regional, and national projects across the US |
225 |
| 63 |
The OIC Agencytheoicagency.com
An award-winning interactive and brand communications agency helping clients in various sectors achieve big things through top-quality marketing strategies and creative work |
214 |
| 64 |
HRC Fertility Managementhavingbabies.com
A Managed Services Organization in the fertility industry providing administrative services to medical practices, including clinics, labs, genetics lab, and surgery centers |
185 |
| 65 |
Courthouse News Servicecourthousenews.com
National news service providing original coverage of civil litigation for lawyers and journalists, from filing to appellate level, by staff reporters |
184 |
| 66 |
Meador Staffing Servicesmeador.com
We specialize in temporary, contract, and direct hire staffing, training, and speakers, connecting job seekers and businesses through strong relationships and industry roots |
179 |
| 67 |
Doheny Eye Institutedoheny.org
A non-profit organization dedicated to advancing vision research, patient care, and education, serving thousands of patients in Los Angeles and Orange Counties |
178 |
| 68 |
The Colt Groupcoltgrp.com
Specializing in on-line leak sealing, repair, and prevention since 1981 We offer innovative solutions to eliminate downtime for critical assets |
178 |
| 69 |
ExchangeRight Real Estateexchangeright.com
Vertical integrated platform managing diversified real estate assets across 47 states, offering secure capital, stable income, and strategic exits for investors nationwide |
176 |
| 70 |
Maranatha High Schoolmaranathahighschool.org
A leading non-denominational Christian high school in Pasadena providing Christ-centered education, rigorous college prep curriculum, and transformative academic programs |
176 |
| 71 |
IMA Los Angelesimacorp.com
A trusted leader in commercial insurance, risk management, surety, and employee benefits consulting, offering tailored solutions to help businesses thrive and succeed |
174 |
| 72 |
KBKG - Tax Credits, Incentives & Cost Recoverykbkg.com
A nationwide tax solutions firm specializing in tax programs, R&D tax credits, cost segregation, transfer pricing, and more Client-focused and value-driven |
173 |
| 73 |
Spokeospokeo.com
A people search engine that provides transparency by reuniting families, preventing fraud, and connecting friends through billions of records |
169 |
| 74 |
Pasadena Humanepasadenahumane.org
Community-supported animal resource center offering shelter, care, adoption, and support programs for animals and their owners in the Greater Los Angeles Area |
169 |
| 75 | 168 | |
| 76 |
Cleaner & Launderercleaner-and-launderer.com
The company provides news and information for the dry cleaning, laundry, and textile industry through newspaper, online, and mobile platforms nationwide |
167 |
| 77 |
Westridge Schoolwestridge.org
An independent girls school in Pasadena, California, offering an active, discussion-based learning environment that emphasizes self-motivation, passion, and impact |
167 |
| 78 |
711 Media711media.tv
A full service advertising agency specializing in integrated direct response campaigns, delivering targeted messages across top performing media outlets |
162 |
| 79 |
B&W Energy Servicesbwenergyservices.com
Specializing in pre-commissioning cleaning services for large-scale projects worldwide, including LNG, power plants, petrochemical, and more, with professional pre-planning and cleaning solutions |
160 |
| 80 |
Pathways In Educationpathwaysedu.org
National network of non-profit schools and learning programs re-engage at-risk youth through blended learning, fostering student-teacher relationships for success |
150 |
| 81 |
Virtualiticsvirtualitics.com
Explainable AI decision intelligence company transforming enterprise and government decision-making with interactive, visually engaging tools rooted in Caltech research |
146 |
| 82 | 146 | |
| 83 |
THE/STUDIOthestudio.com
Digital marketplace connecting brands with manufacturers through innovative software to streamline product creation, simplify online manufacturing processes, and empower creators via custom design. |
136 |
| 84 |
Kellog Brown Root Services Co
A warehousing company located in Pasadena, Texas, specializing in providing services for storing and handling goods |
95 |
| 85 |
Eyebuydirecteyebuydirect.com
This company provides affordable eyewear to make vision correction accessible to everyone, with frames starting as low as $6 |
91 |
| 86 |
CPO Commercecpooutlets.com
A leading online tool retailer founded in 2004, offering a wide selection of brands, discounted prices, and exceptional customer service to millions of customers |
85 |
| 87 |
Techemet LPtechemet.com
Global leader platinum group metals recycling. Smelter, refinery automobile, petrochemical catalyst. Major contributor global recycled PGM market. |
77 |
| 88 |
Satwic Incsatwic.com
Consulting and software development firm providing digital transformation solutions with industry-focused innovation and flexible client-specific IT services. |
72 |
| 89 |
55Haitao Group55haitao.com
Leading e-commerce solution connecting advertisers, publishers, and consumers through various brands and platforms in the global market since 2012 |
66 |
| 90 |
Mission Hospicemissionhospice.net
Providing excellent hospice and palliative care in the Greater Los Angeles area, offering medical, emotional, and spiritual support for patients and families |
65 |
| 91 |
Clifford Swan Investment Counselorscliffordswan.com
Independent investment counseling firm providing personalized wealth management strategies for individuals, families, and mid-sized institutions, with a focus on long-term growth and preservation |
47 |
| 92 |
Cherng Family Trustcherngfamilytrust.com
A multi-generational family office and investment firm focusing on direct private equity, fund investments, real estate portfolio management, and charitable efforts |
44 |
| 93 |
Copa Vidacopa-vida.com
Crafts unique coffee experiences through a three-tiered system, offering classic, lively, and surprising coffee selections for diverse preferences. |
32 |
| 94 |
Leisure Werden & Terrylwtagency.com
A life insurance brokerage agency focusing on providing fast, personalized service, advanced insurance solutions, and high levels of support to clients |
30 |
| 95 |
Grandway Groupgrandway.com
Global asset management and advisory firm specializing in real estate, private equity, and alternative investments Focus on creating value and protecting wealth for international clients |
29 |
| 96 |
Flewelling & Moodyflewelling-moody.com
Design and planning firm since 1928, specializing in creative solutions that meet client needs, enhance functionality, and respect budgets |
27 |
| 97 |
The Spartan Groupthespartangroup.com
An independent investment banking firm founded by ex-Wall Street professionals, focusing on providing top-tier services to entrepreneurs and family business owners nationwide |
26 |
| 98 |
Strategy Asset Managers, LLC.strategyassetmanagers.com
A boutique asset management firm specializing in separately managed accounts, offering global and domestic investments with a focus on quantitative techniques and fundamental analysis |
21 |
| 99 |
The Rule Grouptherulegroup.com
An organization providing personalized insurance, financial services, risk management, and consulting to meet business and personal needs, striving for efficiency and growth |
20 |
| 100 |
DLR Constructionconstructiondlr.com
Full-service design/build company specializing in landscape design, kitchen and bath remodeling, and home landscaping Trusted for superior craftsmanship and client satisfaction |
16 |
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 Oct 24, 2026.
The same list elsewhere in United States
- The largest companies in the United States 91,669
- The largest companies in California 12,813
- The largest companies in New York State 10,485
- The largest companies in Texas 8,086
- The largest companies in Florida 4,945
- The largest companies in Illinois 4,175
- The largest companies in Pennsylvania 3,110
- The largest companies in Massachusetts 3,093
- The largest companies in Georgia 2,632
- The largest companies in Ohio 2,618
- The largest companies in New Jersey 2,569
- The largest companies in Virginia 2,503
- The largest companies in Michigan 2,346
- The largest companies in North Carolina 2,174
- The largest companies in Alabama 1,806
- The largest companies in Washington State 1,785
- The largest companies in Colorado 1,774
- The largest companies in Minnesota 1,700
- The largest companies in Maryland 1,527
- The largest companies in Wisconsin 1,482
- The largest companies in New York 6,920
- The largest companies in San Francisco 2,030
- The largest companies in Houston 1,791
- The largest companies in Chicago 1,668