Biggest UK companies: your guide to the most-valuable British brands

The United Kingdom – and its benchmark stock index, the FTSE 100 – is home to some world-leading blue-chip businesses. But which are the biggest UK companies of all? Find out with our full list.

• The biggest UK companies by market cap
• The biggest UK companies by revenue
• The biggest construction companies in the UK
• The biggest energy companies in the UK
• The biggest insurance companies in the UK

What are the biggest companies in the UK by market cap?

As of October 2023, the most-valuable companies listed in the UK are as follows:

The biggest company in the UK: Shell (LSE:SHEL)

One of the world’s biggest oil and gas providers, Shell has long been one of the most-valuable companies on the London Stock Exchange. A slow recovery from the mass market selloff at the outset of 2020, however, saw the stock lose the top spot to AZN – before it regained it in 2023.

Shell is one of the energy ‘supermajors’, a select group that also includes BP, TotalEnergies and ExxonMobil. Among the supermajors, it is second only to ExxonMobil in terms of revenue.

Shell is formed of a merger between a European company – the Royal Dutch Petroleum Company – and a British one called the “Shell” Transport and Trading Company. The company has multiple listings, on the LSE, Euronext Amsterdam and New York Stock Exchange (NYSE).

How has Shell become the number one UK company once more in 2023? Chiefly due to high oil prices, and increased profits from its gas sales.

The rest of the UK’s biggest companies

2. AstraZeneca (LSE:AZN)

The UK’s second biggest company by market cap is AstraZeneca, the pharmaceutical and biotechnology company best known for its role in developing the Oxford-AstraZeneca Covid-19 vaccine. It created the vaccine in collaboration with Oxford University.

AstraZeneca has multiple products across several areas, including:

• Cardiovascular
• Neuroscience
• Oncology
• Respiratory
• Gastrointestinal

It was formed in 1999 by a merger of Astra AB – a Swedish company – and the British Zeneca Group. The company retains a listing on the Nasdaq Stockholm today, alongside its London Stock Exchange and Nasdaq US listings. It is headquartered at the Cambridge Biomedical Campus.

3. HSBC (LSE:HSBA)

The UK’s most valuable bank by market cap – and Europe’s biggest bank by assets under management – is HSBC. Originally founded in Hong Kong (and called the Hong Kong and Shanghai Banking Corporation), since 1991 HSBC has been based in London.

HSBC shares are dual listed on both the London Stock Exchange and the Hong Kong Stock Exchange, with secondary listings on the NYSE and Bermuda Stock Exchange.

The bank is split into three divisions:

• Commercial banking
• Global banking and markets
• Wealth and personal banking

Wealth and personal banking delivers the most revenue for the company, and caters to over 50 million customers worldwide.

4. Unilever (LSE:ULVR)

Unilever is a global consumer goods company, and the fourth-biggest public UK company by market cap. Headquartered in London, it sells a vast array of products across three divisions:

• Food and refreshments
• Home care
• Beauty and personal care

Some of its top brands include Ben & Jerry’s, Dove, Knorr, Lynx (Axe), Hellman’s and Wall’s. Unilever’s products are sold in 190 countries around the world.

Until 2020, Unilever was headquartered in both the UK and the Netherlands. Today, it is a single entity listed on the London Stock Exchange, though it retains secondary listings on the Euronext Amsterdam and NYSE.

5. BP (LSE:BP)

The fifth biggest UK company is BP, another oil ‘supermajor’. Originally called the Anglo-Persian Oil Company – and then British Petroleum – the business today simply goes by BP and is the fourth-largest oil company in the world by revenue (after ExxonMobil, Shell and TotalEnergies).

Like the other major stocks covered here, BP isn’t listed solely on the London Stock Exchange, featuring on the Frankfurt Stock Exchange and NYSE too.

BP bought a nearly 20% stake in Rosneft, the Russian oil giant, in 2013. It announced that it was selling its stake in 2022 after Russia’s invasion of Ukraine, but still held the stake at the outset of 2023.

6. Diageo (LSE:DGE)

Diageo is a drinks company that has a wide portfolio of alcoholic beverage products, including a specialism in Scotch whisky and spirits. It is listed on the London Stock Exchange, with a secondary listing on the NYSE. 40% of all Scotch whisky is produced by Diageo.

The company’s brands include:

• Johnny Walker
• Guinness
• Smirnoff
• Baileys
• Gordon’s gin
• Tanqueray
• Pimm’s

Diageo also holds a 34% stake in the Moet Hennessy division of LVMH.

7. Rio Tinto (LSE:RIO)

Rio Tinto is an Anglo-Australian mining company – and the second biggest miner in the world after BHP. It has joint head offices in both London and Melbourne and is dual-listed on the LSE and the Australian Securities Exchange (ASX).

RIO is the eighth-biggest company in the UK by market cap, but the first by profit – earning $21 billion in 2022 from revenues of $63 billion.

The company has operations in the mining of several minerals, including iron ore, copper, aluminium, uranium and diamonds. It also refines some minerals.

8. GSK (LSE:GSK)

GSK is a pharmaceutical and biotechnology company headquartered in London, formerly known as GlaxoSmithKline. It was higher among the top UK companies, until a demerger of its consumer healthcare division in July 2022 (into a whole new company, Haleon) saw its market cap fall.

However, GSK remains one of the ten biggest pharmaceutical companies in the world. It has created several medicines listed as essential medicines by the World Health Organisation, including amoxicillin, pyrimethamine and mercaptopurine.

Learn more about GSK’s demerger of Haleon.

9. British American Tobacco (LSE:BATS)

British American Tobacco is a British multinational in the cigarette and tobacco industry. Headquartered in London, it is the largest tobacco company in the world based on sales, with several key brands: including Lucky Strike, Pall Mall and Dunhill.

BATS has also moved into the vaping market, with products such as Vype, Vuse and Glo. It has even made moves to diversify into the legal marijuana market, purchasing a 20% stake in Canadian producer OrganiGram in 2021.

As well as its primary listing on the LSE, BATS stock trades on the Johannesburg Stock Exchange (JSE), and the NYSE. It was first founded in 1902.

10. RELX (LSE:REL)

The final company on our list is RELX (pronounced Rel-ex). RELX is an information and analytics company that operates around the world, providing scientific, medical, legal and technical information to businesses as well as decision-making tools. Like many of the companies covered here, it has multiple listings but is headquartered in London.

Up until 2015, RELX was known as Reed Elsevier. It was formed as the result of a merger between two publishers: Reed International and Elsevier.

The UK’s biggest companies by revenue

Market cap isn’t the only measure of a company’s size. Here are the top British companies by revenue, according to the Global Fortune 500:

As you can see, revenue doesn’t always stack up against market cap. While Shell, BP and HSBC are at the top of both lists, there are some notable differences.

Tesco (LSE:TSCO)

Tesco is the UK’s biggest non-oil company by revenue, but 31st by market cap.

The disparity may be partly explained by Tesco’s comparatively low profit margin. Its £84 billion in revenue translated to £2 billion in 2022 profit, putting the company 15th in terms of the UK’s biggest companies by bottom line.

The intense competition in the supermarket industry, driven partly by ultra-low-cost entrants such as Aldi and Lidl, plus high inflation making goods more expensive, has seen Tesco’s margins shrink.

Tesco is also one of the UK’s top employers, with over 230,000 staff.

Aviva (LSE:AV)

Insurance company Aviva is another stock that has a high revenue that isn’t quite matched by sky-high profit, generating income of £2.7 billion in 2022. It is the 36th biggest UK company by market cap.

Aviva saw its revenues rise but profits fall in 2022, eating further into its profit margin.

The biggest construction companies in the UK

By market cap, the three biggest UK construction companies are:

1. Barratt Developments (LSE:BDEV)

Barratt Developments is the most-valuable builder on the FTSE, sitting at position 77 at the start of 2023. It owns three consumer brands for residential development: Barratt Homes, David Wilson Homes and Barratt London.

2. Berkeley Group (LSE:BKG)

Berkeley Group is the UK’s second-biggest construction company by market cap. As you might have noticed, builders don’t tend to feature at the top of the FTSE 100 – and Berkeley, the second most valuable, still sits as the 80th most valuable company in the country.

3. Taylor Wimpey (LSE:TW)

Another UK housebuilder that sits towards the bottom of the FTSE (just above Persimmon) is Taylor Wimpey. The company was formed from a merger of Taylor Woodrow and George Wimpey in 2007.

The biggest energy companies in the UK

Excluding oil and gas, the three biggest UK energy companies by market cap are:

1. National Grid (LSE:NG)

The National Grid is the UK’s biggest utility company, responsible for operating the electricity and gas network across the country. It also operates in the U.S., where it sells utilities as well.

One of the largest public utilities companies in the world, it is the 14th biggest company in the UK by market cap. It was formed when the UK electricity industry was privatised in the 1990s.

2. SSE (LSE:SSE)

SSE is a utilities company that serves consumers in the UK and Ireland. It was previously called Scottish and Southern Energy, and is headquartered in Perth, Scotland.

The company was formed by a merger between Scottish Hydro-Electric and Southern Electric in 1988.

3. United Utilities (LSE:UU)

United Utilities is the UK’s biggest publicly listed water company. It provides water services to North-West England, including Greater Manchester, Cumbria, Merseyside, Lancashire and parts of Cheshire.

The biggest insurance companies in the UK

By market cap, the three biggest UK insurance companies are:

1. Prudential (LSE:PRU)

The UK’s biggest insurance company by market cap is Prudential. Headquartered in London, it mostly services markets in Africa and Asia, offering life and health insurance, as well as asset management.

Prudential has multiple stock listings, in London Hong Kong, Singapore and New York.

2. Aviva (LSE:AV)

Aviva is a UK insurance company with headquarters in London. It is one of the oldest companies on the London Stock Exchange, tracing its origins back to the Hand in Hand Fire and Life Insurance Society, established in 1696.

The present Aviva was formed in 2000 when Norwich Union merged with CGU. It took on the name Aviva in 2002.

3. Admiral Group (LSE:ADM)

Admiral Group is a UK-based insurance multinational that owns the brands Admiral, Diamond, Bell and Veygo. It also owned the insurance comparison site confused.com until its sale in 2021.

Originally a car insurer, today Admiral offers multiple insurance products including travel, home and pet.