ATLASLargest Companies in the UK by Market Cap (October 2026)
The 615 listed companies ATLAS covers in the UK range from small caps to national champions. These are the 25 largest by market value, converted to US dollars so they can be compared. The three biggest (HSBC, Shell, and AstraZeneca) account for 22% of the combined market value of the whole list.
Data as of Oct 27, 2026. Prices and ratios are the latest stored close; this page refreshes at least every 6 hours.
| # | Company | Price | Market cap |
|---|---|---|---|
| 1 | HSBA.LSEHSBC | £12.83 | $323B |
| 2 | SHEL.LSEShell | £40.00 | $296B |
| 3 | AZN.LSEAstraZeneca | £128.54 | $259B |
| 4 | RR.LSERolls-Royce | £12.35 | $148B |
| 5 | RIO.LSERio Tinto | £62.43 | $144B |
| 6 | ULVR.LSEUnilever | £49.23 | $139B |
| 7 | BP.LSEBP | £6.31 | $126B |
| 8 | BATS.LSEBritish American Tobacco | £45.10 | $125B |
| 9 | GSK.LSEGSK | £19.15 | $97.6B |
| 10 | GLEN.LSEGlencore | £5.38 | $87.9B |
| 11 | LLOY.LSELloyds Banking | £1.03 | $80.9B |
| 12 | NG.LSENational Grid | £12.23 | $80.0B |
| 13 | BARC.LSEBarclays | £4.19 | $76.8B |
| 14 | BA.LSEBAE Systems | £20.12 | $74.9B |
| 15 | NWG.LSENatWest | £6.44 | $71.2B |
| 16 | REL.LSERelx | £29.98 | $65.8B |
| 17 | STAN.LSEStandard Chartered | £20.10 | $61.1B |
| 18 | AAL.LSEAnglo American | £37.47 | $56.1B |
| 19 | LSEG.LSELondon Stock Exchange | £93.40 | $55.0B |
| 20 | DGE.LSEDiageo | £17.76 | $50.9B |
| 21 | CCEP.LSECoca-Cola Europacific Partners | £84.00 | $49.5B |
| 22 | RKT.LSEReckitt Benckiser | £54.84 | $45.7B |
| 23 | TSCO.LSETesco | £5.34 | $43.9B |
| 24 | HLN.LSEHaleon | £3.80 | $43.8B |
| 25 | ANTO.LSEAntofagasta | £31.74 | $43.5B |
Fair value gap: a negative number means the price is below ATLAS fair value. "Chance up" is the probability of a higher close in 21 trading sessions (about a month) in ATLAS's calibrated model.
The top 10 in a sentence
- HSBC (HSBA.LSE) has a market value of $323B. It trades 28% above ATLAS fair value. ATLAS gives it a 52% chance of closing higher in a month.
- Shell (SHEL.LSE) has a market value of $296B. ATLAS puts it close to its fair value. ATLAS gives it a 53% chance of closing higher in a month.
- AstraZeneca (AZN.LSE) has a market value of $259B. ATLAS puts it close to its fair value. ATLAS gives it a 51% chance of closing higher in a month.
- Rolls-Royce (RR.LSE) has a market value of $148B. ATLAS puts it close to its fair value. ATLAS gives it a 50% chance of closing higher in a month.
- Rio Tinto (RIO.LSE) has a market value of $144B. It trades 17% above ATLAS fair value. ATLAS gives it a 52% chance of closing higher in a month.
- Unilever (ULVR.LSE) has a market value of $139B. It trades 16% above ATLAS fair value. ATLAS gives it a 54% chance of closing higher in a month.
- BP (BP.LSE) has a market value of $126B. It trades 38% above ATLAS fair value. ATLAS gives it a 51% chance of closing higher in a month.
- British American Tobacco (BATS.LSE) has a market value of $125B. ATLAS puts it 13% below its fair value. ATLAS gives it a 53% chance of closing higher in a month.
- GSK (GSK.LSE) has a market value of $97.6B. ATLAS puts it 35% below its fair value. ATLAS gives it a 52% chance of closing higher in a month.
- Glencore (GLEN.LSE) has a market value of $87.9B. ATLAS puts it 8% below its fair value. ATLAS gives it a 51% chance of closing higher in a month.
How the largest companies in the UK are ranked
Market value is price times shares outstanding, stored in US dollars so companies quoted in different currencies compare. Where market value and share count do not reconcile (several share classes, dual listings), the company is left out of the size ranking rather than shown with a wrong number.
There are no quality filters here: this is size, not merit. The fair value gap and the one-month probability are shown for context.
Limits: market values move every day with prices and exchange rates, and the figure shown is the latest ATLAS has stored. A large company is not automatically a safe or cheap one. This is information, not investment advice.
Frequently asked questions
What are the largest companies in the UK?
In October 2026, the three largest listed companies in the UK by market value are HSBC, Shell, and AstraZeneca. The three together are worth $877B.
How concentrated is the stock market in the UK?
The three largest companies account for 22% of the combined market value of the 615 companies on the list, a quick measure of concentration.
Is the biggest company the best investment?
No. Size says how much the market values a company today, not whether it is cheap or likely to rise. Compare the fair value gap and the ratios on each company page.
How is market value measured here?
Price times shares outstanding, in US dollars at the latest exchange rate ATLAS has stored. Companies whose share count does not reconcile with their stored value are left out.
How often is this list updated?
Prices and values come from ATLAS's stored data, refreshed every day, and this page is rebuilt at least every 6 hours.
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- Undervalued Stocks in the UK (October 2026)
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Largest companies: other countries
Information only, not investment advice. ATLAS estimates come from statistical models using public data; they can be wrong, and past results do not guarantee future ones. Disclaimer