These London-based companies predominantly operate in telecommunications, financial services, and information services, reflecting a concentration of large, established firms. Among them, Vodafone uses technology to connect people globally, BT Group provides global communication services, RELX offers information-based analytics, and LSEG provides financial indexing and analytic services. Many of these companies are major players with significant employee numbers.
A notable characteristic is the prevalence of companies with a long history, such as BSI, founded in 1901, ACCA, founded in 1904, and The Economist, established in 1843. This indicates a strong presence of mature organizations rather than newly emerging ventures, with a mix of sectors including media like Financial Times and wellness services like Nuffield Health.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
Vodafonevodafone.com
Using technology to connect people globally, drive social change, and improve lives while emphasizing the importance of humanity and collaboration |
142,740 | |||
| 2 | 73,712 | ||||
| 3 | 37,600 | ||||
| 4 | 25,298 | ||||
| 5 |
Revolutrevolut.com
A fintech company on a mission to provide customers with more visibility, control, and freedom over their money through innovative products |
18,462 | |||
| 6 |
Pearsonpearson.com
A global leader in learning, offering digital content, assessments, qualifications, and data to create vibrant and enriching learning experiences worldwide |
13,596 | |||
| 7 | 12,146 | ||||
| 8 |
Clarivateclarivate.com
A global information services provider connecting people and organizations to trusted intelligence in Academia & Government, Life Sciences & Healthcare, and Intellectual Property |
11,385 | |||
| 9 |
BSIbsigroup.com
A global organization with over 100 years of experience in shaping best practices, helping businesses achieve excellence, competence, and sustainable growth |
9,882 | |||
| 10 |
Financial Timesft.com
provides authoritative, accurate business news and information with a large digital subscription base, serving the global business community. |
9,092 | |||
| 11 |
Nuffield Healthnuffieldhealth.com
Leading UK not-for-profit healthcare organization, investing all income back into hospitals, fitness clubs, and wellbeing services to build a healthier nation. |
9,066 | |||
| 12 |
ACCAaccaglobal.com
A global body for professional accountants, providing qualifications and support while promoting ethics, governance, and public interest in the profession |
8,556 | |||
| 13 |
Virgin Activevirginactive.co.uk
Operates large health clubs offering diverse fitness products and services, inspiring active lifestyles with personalized gym and boutique experiences. |
7,690 | |||
| 14 |
The Economisteconomist.com
Global news and analysis provider helping individuals understand the world; offering subscriptions for in-depth insights and respecting personal data privacy |
6,694 | |||
| 15 |
Formula 1formula1.com
Delivering Formula 1's global spectacle through technical infrastructure, data analysis, content production, hospitality programs, and innovative marketing to engage fans worldwide |
6,081 | |||
Want more companies than this list?This page shows the largest ones only. Connect to Tamtam to see every company that matches, filter by size, industry or growth, and reach their decision-makers. | |||||
| 16 |
OnlyFansonlyfans.com
A platform empowering creators to express themselves, monetize content, and build connections with fans in a safe and inclusive environment |
5,941 | |||
| 17 |
IONiongroup.com
Innovative company providing trading and workflow automation software to financial institutions, corporations, and governments, empowering decision-making and accelerating processes |
5,591 | |||
| 18 | 5,267 | ||||
| 19 |
LSEG Data & Analyticslseg.com
A global provider of financial markets data and infrastructure, enabling customers to gain insights through data, feeds, analytics, and workflow solutions |
5,147 | |||
| 20 |
Fitness AIguden.org
Fitness AI is a mobile app using artificial intelligence to personalize workout plans, track progress, and motivate users towards achieving health and fitness goals |
5,137 | |||
| 21 |
Utility Warehouseuw.co.uk
A growing business focusing on simplifying utilities and providing personalized service to help people spend more time on important things |
5,083 | |||
| 22 |
YouGovyougov.com
An international online research and analytics technology group providing unparalleled consumer insights for brands, media owners, and agencies worldwide |
4,691 | |||
| 23 |
Fitch Group, Inc.fitch.group
Global leader in financial information services with operations in 30+ countries Offers credit ratings, research, risk solutions, training, and venture investments Dual headquarters in London and New York |
4,203 | |||
| 24 |
DAZNdazngroup.com
Global sports media innovators using cutting-edge technology to revolutionize the industry, providing sports streaming services and fostering an inclusive, diverse work environment |
4,092 | |||
| 25 |
Futurefutureplc.com
Global specialist media platform creating expert original content through websites, magazines, events, and social spaces reaching millions. |
3,900 | |||
| 26 |
Infobipinfobip.com
Global leader in omnichannel engagement, providing messaging tools and solutions for customer engagement, authentication, and security with a strong focus on quality engineering |
3,501 | |||
| 27 |
TryHackMetryhackme.com
It simplifies learning and teaching Cybersecurity through prebuilt courses and cloud-hosted virtual machines, ideal for CTFs, workshops, and training. |
3,445 | |||
| 28 | 3,323 | ||||
| 29 |
Arsenal Football Clubarsenal.com
Professional football club focusing on winning trophies, developing youth talent, community involvement, maintaining a magnificent stadium, and self-financing operations. |
3,285 | |||
| 30 | 3,161 | ||||
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How this list is built
Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 11, 2026.
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