22 Largest Companies in London

The city’s largest companies work across a wide range of industries including tech, financial services, consumer goods and more.

Written by Abel Rodriguez
London skyline.
Photo: Shutterstock
UPDATED BY
Sara B.T. Thiel | Dec 19, 2024

As the largest city in the United Kingdom, London is a key location for homegrown companies and multinational corporations alike. Some of the city’s largest employers include international tech giants looking for top tech talent, including data analysts, software engineers and cybersecurity experts. Due to its favorable time zone and business-friendly regulatory environment, London is also one of the world’s most important hubs for global finance. From market cap to employee headcount, we’ve picked some of the largest companies in London to know.

Largest Companies in London

  • Google
  • Microsoft
  • HSBC
  • Unilever
  • bp
  • Relx
  • IBM
  • AstraZeneca

 

London’s Largest Companies

Unilever is a global food and consumer goods company. Many recognized names are under its umbrella of brands, including Ben & Jerry’s Ice Cream, TRESemmé, Dove and others. Unilever is headquartered in London, with a presence in over 190 countries.

 

Google, the company synonymous with online search, operates two offices in London, including a 92,000-square-meter building. Apart from its flagship search engine, the company owns a suite of productivity software and has even entered into the generative AI arms race through its Gemini platform.

 

Microsoft is one of the largest tech companies, operating a traditional office in London in addition to an AI development center. The center researches artificial intelligence and contributes to its Copilot platform, which can generate text and images.

 

BP, or British Petroleum, is a globally recognizable oil company headquartered in London. The company is most known for refining crude oil into gasoline, but its operations are much more expansive than that. The company has a hand in all aspects of the oil industry, including extraction and transportation. In recent years, BP has also invested in renewable projects like biofuel development and electric vehicle, or EV, charging locations.

 

Standard Chartered is a global financial institution focusing on commercial services and investment banking. Its offerings enable clients to access capital markets and receive advisory services from experienced financial experts.

 

BT Group, formerly known as British Telecom, is a communications company with several well-known brands under its umbrella, including EE, Plusnet and Openreach. The company provides services like cloud security, fixed-line infrastructure and managed services through its brands. 

 

ServiceNow specializes in workflow automation software that helps enterprise companies streamline operations with clear, integrated processes. Its solutions enable departments like IT and HR to work together seamlessly, fostering innovation and accountability. ServiceNow employs around 26,000 people worldwide and has more than 60 global offices, including a presence in London. 

 

IBM developed enterprise software and has an extensive history of tech development around the world. In the U.K., the company has some 20,000 employees and a large office in London, which contributes to projects like its AI development.

 

Deliveroo’s platform provides rapid delivery services for food, groceries and other items. Founded in 2013, the company has some 9,000 corporate employees to support its sales operations and tech platforms. It has operations across more than 10 countries worldwide.

 

Cencora develops pharmaceutical solutions that aim to improve human and animal health. For example, the company provides extensive drug research and clinical development support and logistics services to securely source, store and transport products. Cencora has an office in the London area and employs for various corporate roles. 

 

AstraZeneca is one of the world’s largest pharmaceutical companies, headquartered in London. The company developed treatments for respiratory and cardiovascular illness but became globally recognized for being one of the first to create a Covid-19 vaccine. During its research and development process, AstraZeneca relies on tech like data science and AI to develop cutting-edge medicine.

 

RELX is a London-based data and analytics company that employs over 36,000 people. The company develops analytics tools that help its customers make informed decisions in areas such as making calculated risks, legal matters and health outcomes.

 

Vodafone is one of the largest mobile service providers in Europe, Africa and Asia. It provides mobile and internet connections to businesses and individual consumers; however, the company also develops AI and quantum computing platforms that can improve its offerings or be integrated into its services.

 

HSBC is one of the world’s largest banks, headquartered in London. The financial institution offers a variety of products, including checking accounts, credit cards, home loans and certificates of deposit, or CDs. Additionally, HSBC is a popular service provider to businesses and high-net-worth individuals, offering custom services and wealth management solutions.

 

Rolls-Royce is a legacy auto manufacturer well known today for its luxury vehicles. However, the company has also developed high-power engines for commercial aircraft, fighter jets and submarines. Rolls-Royce employs over 40,000 people and is headquartered in London.

 

Navan is a corporate travel and expense software company using AI to simplify corporate travel and expense management. Its platform provides organizations with tools to plan travel, monitor expenses and reduce out-of-policy spending. Navan also helps companies track carbon emissions, contributing to more sustainable business practices. The global company has a growing presence in London.

 

Auto Trader operates a digital auto marketplace and supplies dealerships with industry software. The site enables individuals to search and finances new and used vehicles. Meanwhile dealers can use the site to advertise their inventory through the marketplace and other platforms including SMS.

 

WPP provides marketing services and is one of the largest companies in the industry with over 100,000 employees. Its services include advertising, media planning and buying, public relations and branding. The company also develops data platforms that help optimize many of its services.

 

ARM is a semiconductor company that works with some of the biggest names in tech, including Apple. The company does not manufacture chipsets but provides extensive research and electrical expertise to design custom semiconductors for its clients. After delivering the architecture, clients can have them manufactured at outside facilities.

 

Aviva is a British insurance company that offers several products targeted at individual consumers and businesses. For example, it offers personal home, auto, health insurance and other specialized products for businesses, including public liability coverage.

 

Shell is an energy and petrochemical company best known for its oil and gas operations. In addition to refining crude oil into petroleum products, the company generates renewable energy through wind turbines and solar panels and is developing carbon capture and storage technologies.

 

Barclays is a large multinational bank and fintech innovator. The company provides traditional personal and business banking solutions, which differ from country to country, but it has also been one of the first to experiment with new tech in the financial services industry. For example, the company has developed internal uses for blockchain and AI.

 

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