# Top 50 professional services firms in South Holland Tamtam tracks 145 professional services firms headquartered in South Holland. This list ranks the 50 largest by number of employees on LinkedIn, led by Kiwa, MN and Bilfinger Engineering. Their median headcount is 656. Half of them were founded in 1992 or later. The most common headquarters are Rotterdam (25), The Hague (7) and Rijswijk (4). The companies listed here are professional services firms in South Holland, primarily large organizations. They span a range of sectors including IT, financial services, engineering, and insurance. Notable companies include Kiwa, a global leader in Testing, Inspection, and Certification; MN, offering solutions for pension funds and institutional investors; Centric, a partner in digital transformation; and OMA, an international architecture practice. The data shows a concentration of headquarters in Rotterdam, indicating a significant hub for these professional services firms. πŸ‡³πŸ‡± South Holland Β· 50 companies Β· Updated Nov 13, 2026 | # | Company | Industry | Headquarters | Employees | Founded | |---|---|---|---|---|---| | 1 | [Kiwa](https://www.tamtam.ai/c/kiwa) (kiwa.com)
A global leader in Testing, Inspection, and Certification, offering a wide range of services to create trust in products and processes worldwide | Professional Services | πŸ‡³πŸ‡± Rijswijk | 4,320 | | | 2 | [MN](https://www.tamtam.ai/c/mn) (mn.nl)
A Netherlands-based company offering solutions for pension funds and institutional investors, specializing in investment management, pension administration, and management support | Financial Services | πŸ‡³πŸ‡± The Hague | 3,291 | | | 3 | [Bilfinger Engineering](https://www.tamtam.ai/c/bilfinger-engineering) (bilfinger.com)
Multidisciplinary engineering consultancy offering future-proof and sustainable solutions for industrial projects across various markets with a focus on project management and procurement | Engineering Services | πŸ‡³πŸ‡± Schiedam | 2,973 | 1945 | | 4 | [Centric](https://www.tamtam.ai/c/centric) (centric.eu)
A leading partner in digital transformation, providing software solutions, IT assessments, cloud services, staffing, and business process outsourcing to a diverse range of clients | IT Services and IT Consulting | πŸ‡³πŸ‡± Gouda | 2,900 | 1992 | | 5 | [ICT Group](https://www.tamtam.ai/c/ict-group) (ict.eu)
Leading European provider industrial technology solutions. Delivers consultancy, software development, project solutions, managed services across vital sectors: automotive, high tech, industry, infrastructure, logistics, public mobility and safety. | IT Services and IT Consulting | πŸ‡³πŸ‡± Barendrecht | 2,462 | | | 6 | [CED Europe](https://www.tamtam.ai/c/ced-europe) (cedgroup.eu)
A European tech-enabled insurance services platform with a focus on expert claims management, innovation, and customer satisfaction through technology and personalized solutions | Insurance | πŸ‡³πŸ‡± Capelle aan den IJssel | 1,941 | | | 7 | [OMA](https://www.tamtam.ai/c/oma) (oma.com)
International architecture practice with a research and design studio, led by eight partners, known for innovative buildings worldwide, with offices in multiple cities | Architecture and Planning | πŸ‡³πŸ‡± Rotterdam | 1,905 | 1975 | | 8 | [Zorgwerk](https://www.tamtam.ai/c/zorgwerk) (zorgwerk.nl)
Specializing in staffing solutions for the healthcare sector, providing excellent service to match supply and demand, with a focus on values like happiness and connectedness | Staffing and Recruiting | πŸ‡³πŸ‡± Rotterdam | 1,806 | 1997 | | 9 | [Robeco](https://www.tamtam.ai/c/robeco) (robeco.com)
An international asset manager specializing in sustainable investing, offering active investment strategies for institutional and private investors across various asset classes | Financial Services | πŸ‡³πŸ‡± Rotterdam | 1,482 | 1929 | | 10 | [Iv](https://www.tamtam.ai/c/iv) (iv.nl)
Specialist engineers solving complex issues related to energy transition, climate change, and societal resilience through innovative design solutions for various projects | Engineering Services | πŸ‡³πŸ‡± Papendrecht | 1,439 | 1949 | | 11 | [CGI Nederland](https://www.tamtam.ai/c/cgi-nederland) (cgi.com)
Established in 1976, a global leader in IT and business consultancy, offering insights and results-driven solutions across 21 industries worldwide | IT Services and IT Consulting | πŸ‡³πŸ‡± Rotterdam | 1,435 | 1976 | | 12 | [Bilfinger BelgiΓ« & Nederland](https://www.tamtam.ai/c/bilfinger-belgie-and-nederland) (bilfinger.com)
Industrial benchmark for projects and maintenance of industrial assets, ensuring safety and availability for clients in Belgium and the Netherlands Services include insulation, scaffolding, and more | Commercial and Industrial Machinery Maintenance | πŸ‡³πŸ‡± Rotterdam | 1,354 | 1950 | | 13 | [Moore DRV](https://www.tamtam.ai/c/moore-drv) (moore-drv.nl)
Accountants and advisors supporting entrepreneurs in the real economy with expert insights, solutions, and support for lasting improvements in business performance | Financial Services | πŸ‡³πŸ‡± Rotterdam | 1,335 | 1922 | | 14 | [Customs Support Group](https://www.tamtam.ai/c/customs-support-group) (customssupport.com)
Leading European provider of customs and trade solutions enhancing cross-border operations, compliance, cost optimization, and operational efficiency. | International Trade and Development | πŸ‡³πŸ‡± Rotterdam | 1,037 | 1999 | | 15 | [Kiwa Nederland](https://www.tamtam.ai/c/kiwa-nederland) (kiwa.com)
A global leader in testing, inspection, and certification services, ensuring trust in products, services, processes, systems, and employees for clients worldwide | Professional Services | πŸ‡³πŸ‡± Rijswijk | 984 | | | 16 | [Ecorys](https://www.tamtam.ai/c/ecorys) (ecorys.com)
This company provides research, consulting, communications, and management services to develop, deliver, and evaluate public policy on an international scale | Research Services | πŸ‡³πŸ‡± Rotterdam | 954 | 1929 | | 17 | [Aethon.nl](https://www.tamtam.ai/c/aethon-nl) (aethon.nl)
Connecting talented individuals to meaningful work in various social sectors through training programs, ensuring continuity and flexibility for organizations while supporting career growth for individuals | Staffing and Recruiting | πŸ‡³πŸ‡± Rijswijk | 924 | 2005 | | 18 | [AKD](https://www.tamtam.ai/c/akd) (akd.eu)
Delivers high-quality legal services and handles tax matters across nearly all legal fields in the Benelux region, involved in high-profile cases. | Law Practice | πŸ‡³πŸ‡± Amsterdam | 919 | 1917 | | 19 | [Deerns](https://www.tamtam.ai/c/deerns) (deerns.com)
Independent engineering firm specializing in technical consulting and engineering solutions for various sectors worldwide, delivering high-quality services tailored to client's unique needs since 1928 | Engineering Services | πŸ‡³πŸ‡± The Hague | 800 | 1928 | | 20 | [Grant Thornton Netherlands](https://www.tamtam.ai/c/grant-thornton-netherlands) (grantthornton.nl)
A member of Grant Thornton International Ltd, offering audit, tax, and advisory services with a global network of professionals | Professional Services | πŸ‡³πŸ‡± Alphen aan den Rijn | 776 | | | 21 | [TOS People](https://www.tamtam.ai/c/tos-people) (tospeople.com)
A family-owned maritime services provider offering selection, secondment, payroll, and training for various industries worldwide, focusing on people and quality service | Staffing and Recruiting | πŸ‡³πŸ‡± Rotterdam | 763 | 1992 | | 22 | [WTS Energy](https://www.tamtam.ai/c/wts-energy) (wtsenergy.com)
Supporting organizations in the Energy Transition by providing expertise, flexibility, and technology for sustainable power generation projects through trusted partnerships and consistent service quality | Staffing and Recruiting | πŸ‡³πŸ‡± The Hague | 733 | 2000 | | 23 | [GGN](https://www.tamtam.ai/c/ggn) (ggn.nl)
GGN is the largest debt collection and bailiff company in the Netherlands, focusing on helping individuals with financial difficulties while ensuring businesses get paid | Financial Services | πŸ‡³πŸ‡± Rotterdam | 720 | 2002 | | 24 | [MetrixLab](https://www.tamtam.ai/c/metrixlab) (tolunacorporate.com)
Global market research and insights provider challenging industry norms with technology and expert-driven solutions for brand impact and sustainable growth worldwide | Market Research | πŸ‡³πŸ‡± Rotterdam | 662 | 1999 | | 25 | [Daan](https://www.tamtam.ai/c/daan) (daan.eu)
A company that matches individuals with passion and ambition to suitable jobs in healthcare, education, and social security through personalized support and development opportunities | Staffing and Recruiting | πŸ‡³πŸ‡± Rotterdam | 656 | 2012 | | 26 | [Schoo & Co.](https://www.tamtam.ai/c/schoo-and-co) (schooco.nl)
A global consulting firm offering specialized services to insurance, shipping, and off-shore industries with a focus on expertise, sustainability, and client-centric approach | Maritime Transportation | πŸ‡³πŸ‡± Rotterdam | 629 | 1940 | | 27 | [KH Engineering](https://www.tamtam.ai/c/kh-engineering) (khe.eu)
Multidisciplinary engineering firm offering full-service support for projects worldwide Specializes in innovative technological solutions with a focus on safety and sustainability | Industrial Machinery Manufacturing | πŸ‡³πŸ‡± Schiedam | 570 | 1949 | | 28 | [VPS](https://www.tamtam.ai/c/vps) (vpsveritas.com)
A global leader in maritime decarbonisation advisory services, providing innovative testing and inspection solutions to optimize performance while reducing environmental impact | Professional Services | πŸ‡³πŸ‡± Rotterdam | 561 | | | 29 | [DevOn](https://www.tamtam.ai/c/devon) (devon.nl)
Accelerating enterprise success in the digital world through DevOps consultancy, transformation, training, and high performance teams specializing in software delivery and IT professionals | IT Services and IT Consulting | πŸ‡³πŸ‡± Delft | 545 | 2016 | | 30 | [ICTU](https://www.tamtam.ai/c/ictu) (ictu.nl)
ICTU helps governments improve their services through innovative, high-quality ICT solutions, supporting collaboration between government levels and achieving concrete results for citizens and businesses | IT Services and IT Consulting | πŸ‡³πŸ‡± The Hague | 544 | 2001 | | 31 | [DC](https://www.tamtam.ai/c/dc-rotterdam)
Multidisciplinary design agency specializing in developing visual identities for print and web, serving diverse clients in art, culture, brands, education, and government sectors | Design Services | πŸ‡³πŸ‡± Rotterdam | 532 | 1999 | | 32 | [SKIM](https://www.tamtam.ai/c/skim) (skimgroup.com)
Global insights agency specializing in understanding decision-making for consumers, healthcare, and B2B professionals Offers practical marketing solutions through rigorous research techniques | Business Consulting and Services | πŸ‡³πŸ‡± Rotterdam | 513 | 1979 | | 33 | [Rua](https://www.tamtam.ai/c/rua) (rua.nu)
RUA is a consultancy specializing in environmental management and participation, providing support in communication, stakeholder engagement, and community relations | Public Relations and Communications Services | πŸ‡³πŸ‡± Rotterdam | 500 | 2021 | | 34 | [BPO bv](https://www.tamtam.ai/c/bpo-bv) (bpo.nl)
Specializing in product development, BPO offers end-to-end design solutions including analysis, prototypes, materials, sustainability, and testing for manufacturing efficiency | Engineering Services | πŸ‡³πŸ‡± Delft | 490 | 1987 | | 35 | [216](https://www.tamtam.ai/c/216) (216.nl)
This financial service provider uses knowledge, innovation, and technology to help entrepreneurs with automated, data-driven systems and comprehensive services | Financial Services | πŸ‡³πŸ‡± The Hague | 485 | 2015 | | 36 | [valantic NL](https://www.tamtam.ai/c/valantic-nl) (valantic.com)
Develops digital solutions, consulting services, and software, focusing on e-business, digital commerce, and marketing to integrate digital channels for client growth. | Business Consulting and Services | πŸ‡³πŸ‡± Rotterdam | 478 | 1992 | | 37 | [iPS Powerful People (B Corpβ„’)](https://www.tamtam.ai/c/ips-powerful-people-b-corp) (ipspowerfulpeople.com)
An international personnel provider in Maritime, Energy, Tunnelling & Civil industries offering transparent, flexible, and professional personnel solutions with global service | Staffing and Recruiting | πŸ‡³πŸ‡± Capelle aan den IJssel | 466 | 1988 | | 38 | [CarriΓ¨re Uitzendbureau](https://www.tamtam.ai/c/carriere-uitzendbureau) (carriere.com)
Committed to improving organizational performance, CarriΓ¨re focuses on HR processes and values customer satisfaction, knowledge sharing, and top-notch service provision | Staffing and Recruiting | πŸ‡³πŸ‡± Rotterdam | 453 | 2010 | | 39 | [Cardano](https://www.tamtam.ai/c/cardano) (cardano.nl)
An investment management and advisory business focusing on risk and sustainability, supporting pension schemes to secure resilient financial outcomes for savers and society | Financial Services | πŸ‡³πŸ‡± Rotterdam | 448 | 2000 | | 40 | [IDDS](https://www.tamtam.ai/c/idds) (idds.nl)
IDDS is a nationwide engineering and consulting firm, offering expertise in various areas such as environment, archaeology, water, and civil engineering | Real Estate | πŸ‡³πŸ‡± Noordwijk | 435 | 1988 | | 41 | [Visser & Visser](https://www.tamtam.ai/c/visser-and-visser) (visser-visser.nl)
A team of specialists at this company assists with international business ventures in the Netherlands, providing expertise in tax, employment law, and finance Through PrimeGlobal, they offer global support | Financial Services | πŸ‡³πŸ‡± Rotterdam | 434 | 1989 | | 42 | [Pels Rijcken](https://www.tamtam.ai/c/pels-rijcken) (pelsrijcken.nl)
Specializing in legal services, our team at Pels Rijcken provides tailored solutions for leading clients, particularly in the public sector Visit our website for more information | Law Practice | πŸ‡³πŸ‡± The Hague | 412 | 1969 | | 43 | [TWD](https://www.tamtam.ai/c/twd) (twd.nl)
Providing custom-designed solutions for offshore and heavy civil installation projects, including innovations, seafastening structures, lifting tools, and more Contact us for practical solutions 24/7 | Civil Engineering | πŸ‡³πŸ‡± Rotterdam | 406 | | | 44 | [Recruitment Company](https://www.tamtam.ai/c/recruitment-company) (recruitmentcompany.nl)
Specializing in management search for industries such as technical, production, food, and logistics, recruiting talented managers with 5+ years experience and bachelor/master degrees | Staffing and Recruiting | πŸ‡³πŸ‡± Rotterdam | 389 | 1999 | | 45 | [Public Support](https://www.tamtam.ai/c/public-support) (publicsupport.nl)
Public Support is a team of supportive professionals dedicated to helping others excel, especially in the public sector, creating space for growth and trust | Staffing and Recruiting | πŸ‡³πŸ‡± Lisse | 387 | 2009 | | 46 | [Van Ameyde Group](https://www.tamtam.ai/c/van-ameyde-group) (vanameyde.com)
Global professional services firm specializing in insurance, claims, and risk management, providing swift solutions and unrivaled systems to secure clients' success worldwide | Insurance | πŸ‡³πŸ‡± Rijswijk | 382 | | | 47 | [MVRDV](https://www.tamtam.ai/c/mvrdv) (mvrdv.com)
A Rotterdam-based architectural firm specializing in innovative and sustainable solutions for urban and architectural projects worldwide through collaborative and research-based design methods | Architecture and Planning | πŸ‡³πŸ‡± Rotterdam | 370 | 1993 | | 48 | [Luba](https://www.tamtam.ai/c/luba) (luba.nl)
Leading staffing agency for SMEs, specializing in quick matches between job vacancies and local talent through personalized communication and 50 nationwide branches | Human Resources Services | πŸ‡³πŸ‡± Leiden | 355 | 1968 | | 49 | [Rebel](https://www.tamtam.ai/c/rebel) (rebelgroup.com)
Development and advisory of public-private partnerships, innovative financing, project delivery, investment management, and strategic consulting across sustainability and social sectors. | Strategic Management Services | πŸ‡³πŸ‡± Rotterdam | 346 | 2002 | | 50 | [Deerns Nederland](https://www.tamtam.ai/c/deerns-nederland) (deerns.com)
An independent engineering firm providing consulting and engineering solutions globally, specializing in Airports, Healthcare, Data Centers, Laboratories, Cleanrooms, and Commercial Real Estate | Design Services | πŸ‡³πŸ‡± The Hague | 343 | 1928 | ## 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 13, 2026. ## More company lists in South Holland - [The largest companies in South Holland](https://www.tamtam.ai/l/largest-companies-south-holland) (2,508) - [Multinational companies in South Holland](https://www.tamtam.ai/l/multinational-companies-south-holland) (559) - [Transportation, Logistics, Supply Chain and Storage companies in South Holland](https://www.tamtam.ai/l/transportation-logistics-supply-chain-and-storage-companies-south-holland) (276) - [Logistics companies in South Holland](https://www.tamtam.ai/l/logistics-companies-south-holland) (263) - [Retail chains in South Holland](https://www.tamtam.ai/l/retail-chains-south-holland) (188) - [Critical infrastructure operators in South Holland](https://www.tamtam.ai/l/critical-infrastructure-operators-south-holland) (152) - [Truck Transportation companies in South Holland](https://www.tamtam.ai/l/truck-transportation-companies-south-holland) (145) - [Software Development companies in South Holland](https://www.tamtam.ai/l/software-development-companies-south-holland) (142) - [Companies with in-house R&D in South Holland](https://www.tamtam.ai/l/r-and-d-companies-south-holland) (140) - [SaaS companies in South Holland](https://www.tamtam.ai/l/saas-companies-south-holland) (137) - [Manufacturers in South Holland](https://www.tamtam.ai/l/manufacturers-south-holland) (134) - [Family-owned companies in South Holland](https://www.tamtam.ai/l/family-owned-companies-south-holland) (128) - [Healthcare providers in South Holland](https://www.tamtam.ai/l/healthcare-providers-south-holland) (124) - [IT Services and IT Consulting companies in South Holland](https://www.tamtam.ai/l/it-services-and-it-consulting-companies-south-holland) (121) - [Financial services firms in South Holland](https://www.tamtam.ai/l/financial-services-firms-south-holland) (120) - [Education providers in South Holland](https://www.tamtam.ai/l/education-companies-south-holland) (111) - [Hospitals and Health Care companies in South Holland](https://www.tamtam.ai/l/hospitals-and-health-care-companies-south-holland) (109) - [Financial Services companies in South Holland](https://www.tamtam.ai/l/financial-services-companies-south-holland) (107) - [Consulting firms in South Holland](https://www.tamtam.ai/l/consulting-firms-south-holland) (106) - [Distributors and wholesalers in South Holland](https://www.tamtam.ai/l/distributors-and-wholesalers-south-holland) (96) - [IT services companies in South Holland](https://www.tamtam.ai/l/it-services-companies-south-holland) (93) - [Hardware manufacturers in South Holland](https://www.tamtam.ai/l/hardware-companies-south-holland) (86) - [Hotel and hospitality groups in South Holland](https://www.tamtam.ai/l/hospitality-groups-south-holland) (86) - [Public sector organisations in South Holland](https://www.tamtam.ai/l/public-sector-organisations-south-holland) (82) ## The same list elsewhere in Netherlands - [Professional services firms in the Netherlands](https://www.tamtam.ai/l/professional-services-firms-netherlands) (739) - [Professional services firms in North Holland](https://www.tamtam.ai/l/professional-services-firms-north-holland) (207) - [Professional services firms in North Brabant](https://www.tamtam.ai/l/professional-services-firms-north-brabant) (106) - [Professional services firms in Gelderland](https://www.tamtam.ai/l/professional-services-firms-gelderland) (44) - [Professional services firms in Overijssel](https://www.tamtam.ai/l/professional-services-firms-overijssel) (34) - [Professional services firms in Amsterdam](https://www.tamtam.ai/l/professional-services-firms-amsterdam) (153) - [Professional services firms in Utrecht](https://www.tamtam.ai/l/professional-services-firms-utrecht) (80) - [Professional services firms in Rotterdam](https://www.tamtam.ai/l/professional-services-firms-rotterdam) (61) - [Professional services firms in Eindhoven](https://www.tamtam.ai/l/professional-services-firms-eindhoven) (26) ## The same list elsewhere - [Professional services firms in the world](https://www.tamtam.ai/l/professional-services-firms-in-the-world) (24,737) - [Professional services firms in Europe](https://www.tamtam.ai/l/professional-services-firms-in-europe) (13,699) --- Source: https://www.tamtam.ai/l/professional-services-firms-south-holland