Top UK Companies in 2025

The UK is home to some of the most iconic brands and successful companies globally. From major players in pharmaceuticals to energy and finance, these companies are driving the nation’s economy and demonstrating the UK’s strong position in global business. Below is a look at the top 10 UK companies by market capitalization in 2025, highlighting their operations and their impact on both the UK and the global market.

10. GSK

Market Cap: £55.03 billion
GSK (GlaxoSmithKline) is a global healthcare company that specializes in medicines, vaccines, and consumer healthcare products. Known for its focus on research and development, GSK addresses major health challenges worldwide, particularly in respiratory diseases, HIV, and immunization. The company, formed by the 2000 merger of Glaxo Wellcome and SmithKline Beecham, operates in over 100 countries. GSK continues to innovate, working on solutions that improve public health, all while maintaining strong sustainability efforts across its manufacturing processes.

Key Subsidiaries: ViiV Healthcare (HIV treatment), Stiefel Laboratories (dermatology)
Highlights: A strong emphasis on research partnerships and sustainability within the UK biotech scene.

9. London Stock Exchange Group (LSEG)

Market Cap: £62.52 billion
LSEG is a leading player in financial market infrastructure and data analytics, enabling global trading in equities and derivatives. The company has expanded its reach through acquisitions like Refinitiv and FTSE Russell, providing essential financial data and benchmarks. LSEG plays a pivotal role in connecting UK businesses with global capital flows, offering services that support both traditional and electronic trading.

Key Subsidiaries: Refinitiv (financial data), FTSE Russell (index provider)
Highlights: A major link between UK businesses and international markets, investing heavily in technological advances to support modern trading.

8. British American Tobacco (BAT)

Market Cap: £64.11 billion
BAT is one of the largest companies in the UK, known for its tobacco products, including traditional cigarettes and newer alternatives like e-cigarettes and heated tobacco. Operating in over 180 countries, BAT focuses on innovation to meet changing consumer demands and regulatory challenges. While it faces health policy pressures, BAT continues to invest in next-generation nicotine products as part of its long-term transformation.

Key Subsidiaries: Reynolds American (USA), Nicoventures (reduced-risk products)
Highlights: A strong commitment to evolving its product range responsibly, adapting to shifting global trends and regulations.

7. BP

Market Cap: £67.66 billion
BP, one of the largest energy companies globally, combines oil and gas operations with increasing investments in renewable energy sources such as solar, wind, and hydrogen. With a history dating back to 1909, BP is focusing on decarbonization and green energy solutions, aligning its strategy with global climate goals. BP’s efforts in environmental responsibility, including carbon capture and hydrogen research, showcase the company’s pivot towards sustainable energy.

Key Subsidiaries: BP Solar (renewables), Castrol (industrial lubricants)
Highlights: A key player in the UK’s energy sector, embracing innovation to meet future energy demands sustainably.

6. RELX

Market Cap: £72.36 billion
RELX offers essential data analytics and information services across various industries, including legal, scientific, and risk management sectors. The company utilizes AI and cloud-based platforms to deliver real-time insights that help businesses optimize decision-making. RELX is particularly known for its seamless transition from traditional publishing to modern data-driven solutions.

Key Subsidiaries: LexisNexis (legal analytics), Elsevier (academic publishing)
Highlights: RELX has positioned itself as a leader in bridging print heritage with advanced digital services.

5. Rio Tinto

Market Cap: £84.30 billion
Rio Tinto is a global leader in the mining industry, producing essential minerals like iron ore, copper, and aluminum. These materials play a critical role in manufacturing, construction, and high-tech industries worldwide. With operations across multiple continents, Rio Tinto emphasizes environmental responsibility, using advanced technologies like autonomous hauling and biodiversity projects to reduce its ecological footprint.

Key Subsidiaries: Turquoise Hill Resources, Kennecott Utah Copper
Highlights: Focus on sustainability and digital mining innovation to enhance efficiency and safety.

4. Unilever

Market Cap: £111.77 billion
Unilever is a multinational company known for its wide range of consumer goods, from food and beverages to personal care products. With iconic brands like Dove, Lipton, and Ben & Jerry’s, Unilever is committed to sustainability and ethical consumerism. The company continues to lead in corporate social responsibility, working towards reducing plastic waste and improving product nutrition.

Key Subsidiaries: Dove, Ben & Jerry’s, Hellmann’s
Highlights: Unilever’s strong focus on sustainability and ethical practices positions it as a leader in the consumer goods market.

3. HSBC Holdings

Market Cap: £146.22 billion
HSBC is a global banking and financial services giant, providing services in commercial financing, wealth management, and personal banking. The company’s long history of connecting East and West through trade and capital flows positions it as a key player in global finance. HSBC is also investing heavily in digital solutions and sustainable finance, making it a major force in the modern banking landscape.

Key Subsidiaries: HSBC Bank USA, Hang Seng Bank, HSBC Private Bank
Highlights: Focus on digital banking solutions and sustainability initiatives, helping shape the future of global finance.

2. Shell

Market Cap: £163.31 billion
Shell, a leader in the global energy sector, has traditionally focused on oil and gas but is increasingly investing in renewable energy sources, such as solar, wind, and hydrogen. Shell is adapting to climate pressures by accelerating its transition to net-zero emissions through electrification and carbon offsets, signaling a commitment to a more sustainable energy future.

Key Subsidiaries: Shell Energy (renewables), Shell Chemicals (petrochemicals)
Highlights: Shell’s expansion into alternative fuels and its growing hydrogen infrastructure reflect its shift towards sustainable energy solutions.

1. AstraZeneca

Market Cap: £168.14 billion
AstraZeneca stands at the top of the UK’s corporate rankings, known for its life-saving and life-enhancing pharmaceutical products. The company is a global leader in oncology, cardiovascular, respiratory, and renal medications, among others. With a strong focus on research and development, AstraZeneca continues to pioneer breakthroughs in healthcare, including vaccine research and gene therapies.

Key Subsidiaries: Alexion Pharmaceuticals, MedImmune, Acerta Pharma
Highlights: AstraZeneca’s innovative work in the biomedical field and its response to global health challenges underscore its critical role in improving public health worldwide.

Honorable Mentions

Several other prominent UK companies are making an impact in 2025, including:

• National Grid PLC (£46.43 billion), focused on energy transmission and renewable grid integration.
• Compass Group PLC (£45.36 billion), a global leader in foodservice and catering.
• Glencore PLC (£45.07 billion), a major player in commodity trading and resource extraction.
• Barclays PLC (£40.71 billion), a key player in retail and corporate banking.
• Rolls-Royce Holdings PLC (£39.23 billion), known for its innovation in aerospace and defense technologies.

These companies continue to shape the UK’s economy, driving innovation and playing a critical role in their respective sectors.