London's data and analytics sector is characterized by large, established firms. RELX provides information-based analytics across various industries, while LSEG offers financial indexing and technology solutions. Kantar specializes in marketing data and analytics, and Clarivate delivers trusted intelligence to academia, life sciences, and intellectual property.
A notable pattern among these companies is their focus on information services and financial analytics. Many, including Informa and ION, were founded around the turn of the millennium, indicating a period of significant growth and establishment in the sector.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 | 37,600 | ||||
| 2 | 25,298 | ||||
| 3 |
Kantarkantar.com
Global leader in marketing data and analytics with deep expertise, innovative technology, and insights to help clients understand people and drive growth worldwide |
24,976 | |||
| 4 |
Smollansmollan.com
Partners with brands and retailers, building solutions that drive growth and create opportunities at the point of purchase. |
13,502 | |||
| 5 |
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 | |||
| 6 |
Publicis Mediapublicisgroupe.com
A global media company within Publicis Groupe, employing data-driven solutions and platform-based technologies to deliver client value and drive growth internationally |
11,033 | |||
| 7 |
Informainforma.com
Leading international business in events, digital services, and academic knowledge, connecting specialists worldwide to learn, know, and do more in their fields |
9,410 | |||
| 8 |
Apex Group Ltd (UK & Ireland)apexgroup.com
A global financial services provider with offices in over 50 countries, offering a wide range of services to asset managers, capital markets, and family offices |
9,281 | |||
| 9 |
Acuity Analyticsacuityanalytics.com
Provides bespoke research, analytics, and technology solutions to financial services, helping institutions operate efficiently and unlock human capital to drive revenue. |
7,619 | |||
| 10 |
IONiongroup.com
Innovative company providing trading and workflow automation software to financial institutions, corporations, and governments, empowering decision-making and accelerating processes |
5,591 | |||
| 11 |
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 | |||
| 12 |
YouGovyougov.com
An international online research and analytics technology group providing unparalleled consumer insights for brands, media owners, and agencies worldwide |
4,691 | |||
| 13 |
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 | |||
| 14 |
Playtechplaytech.com
Leading software and services supplier for the gambling industry, offering omni-channel solutions for online, mobile, and retail operations, including financial trading. |
3,735 | |||
| 15 |
Worldpanelworldpanelbynumerator.com
Experts in global shopper and consumer behavior providing analytics for retail and marketing strategies, enabling smarter decisions for a better world |
3,437 | |||
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 |
Stats Performstatsperform.com
Global leader in sports technology providing unrivaled AI-powered sports data for media, tech, betting, and team performance solutions |
3,359 | |||
| 17 |
Tolunatolunacorporate.com
Global leader providing advanced technology and comprehensive solutions for data-driven market research, leveraging AI and extensive global panels. |
3,218 | |||
| 18 |
Genius Sportsgeniussports.com
This company delivers technology and expertise to sports, betting, and media partners worldwide, enhancing data collection, fan engagement, and overall performance |
3,054 | |||
| 19 |
Two Circlestwocircles.com
Management of extensive fan data to enhance audience engagement and increase revenue for leading sports and entertainment organizations worldwide. |
2,877 | |||
| 20 |
TradingViewtradingview.com
Social network and charting platform for traders and investors, used by 50 million+ users worldwide with open source charts used by financial giants |
2,761 | |||
| 21 |
ICAPtpicap.com
A leading markets operator providing electronic execution and information services for wholesale market participants, facilitating capital flow and supporting borrowing needs |
2,750 | |||
| 22 |
GlobalData Plcglobaldata.com
A leading information services company helps organizations and decision-makers predict the future, make informed decisions, and gain a competitive edge |
2,711 | |||
| 23 |
Third Bridge Groupthirdbridge.com
A global investment research firm delivering unique insights to help investment firms make better decisions through a team of 1,200+ employees |
2,438 | |||
| 24 |
Dialecticadialectica.io
A B2B information services firm connecting professionals with industry experts worldwide through a trusted knowledge-sharing platform, recognized for growth and workplace excellence |
2,400 | |||
| 25 |
Qube Research & Technologiesqube-rt.com
Global quant and systematic investment manager using technology and data for scientific approach to investing, driving innovation for high quality returns Multiple open positions available |
2,393 | |||
| 26 |
London Stock Exchangelondonstockexchange.com
Global financial marketplace providing extensive access to capital markets and liquidity across multiple asset classes for international businesses, governments, and investment funds. |
2,358 | |||
| 27 |
Euromonitor Internationaleuromonitor.com
Provides comprehensive global data analytics and research on markets, industries, economies, and consumers to support strategic business growth decisions. |
2,176 | |||
| 28 |
CACI Ltdcaci.co.uk
Provides data, marketing, IT solutions, software, consulting services, and managed services to public and private sector clients. Improves sales, marketing, operations, and reduces costs. |
2,025 | |||
| 29 |
Argus Mediaargusmedia.com
Provides price assessments, news, analytics, consulting, data tools, and conferences for global energy and commodity market transparency and decision-making. |
2,024 | |||
| 30 | 1,896 | ||||
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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 12, 2026.
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