HomeReference › London Stock Exchange

London Stock Exchange (LSE) — How It Works

The London Stock Exchange (LSE) is one of the oldest and largest stock exchanges in the world, with roots dating back to 1698. Part of the London Stock Exchange Group (LSEG), it lists over 2,000 companies from more than 60 countries and is the primary venue for European equity trading. Its flagship index, the FTSE 100, tracks the 100 largest UK-listed companies by market capitalization.

How the LSE Works

The LSE operates as an electronic order-driven market. Unlike the NYSE, which uses designated market makers on a physical trading floor, the LSE runs entirely on electronic systems. Its main trading platform is called SETS (Stock Exchange Electronic Trading Service), which matches buy and sell orders automatically.

The exchange hosts two main markets: the Main Market for established companies that meet stringent listing requirements, and AIM (Alternative Investment Market) for smaller, growth-oriented companies with lighter regulatory standards. This dual structure makes London attractive to both blue-chip corporations and emerging businesses.

Key Facts at a Glance

DetailInformation
Founded1801 (informal trading from 1698)
LocationPaternoster Square, London, UK
Parent CompanyLondon Stock Exchange Group (LSEG)
Trading Hours8:00 AM – 4:30 PM GMT (3:00 AM – 11:30 AM ET)
Number of Listed Companies~2,000+
Main IndexFTSE 100
CurrencyGBP (British Pound Sterling)
Market TypeElectronic order-driven

LSE vs. NYSE

FeatureLondon Stock ExchangeNYSE
LocationLondon, UKNew York, USA
Founded18011792
Trading ModelFully electronic (SETS)Hybrid (electronic + floor)
Primary IndexFTSE 100Dow Jones
CurrencyGBPUSD
Growth MarketAIMNYSE American
Parent CompanyLSEGICE

Major Indices on the LSE

The FTSE 100 is the headline index, tracking the 100 largest companies by market cap. The FTSE 250 covers the next 250 mid-cap companies and is often considered a better gauge of the domestic UK economy since FTSE 100 companies earn most of their revenue internationally. The FTSE All-Share combines both, giving investors broad UK market exposure.

What Makes the LSE Unique

London’s time zone advantage is significant — it overlaps with Asian markets in the morning and U.S. markets in the afternoon, making it a natural hub for international trading. The LSE is also a major listing venue for mining companies, energy firms, and financial institutions from around the world. Many companies choose to dual-list in London alongside their home exchange.

LSEG also owns Refinitiv (acquired in 2021), one of the world’s largest financial data providers, and FTSE Russell, which creates widely used indices followed by trillions in passive assets.

Analyst Tip
When analyzing FTSE 100 companies, remember that roughly 75% of their revenue comes from outside the UK. A weaker British pound actually boosts FTSE 100 earnings because overseas revenue translates into more pounds. The FTSE 250 is the better proxy for UK domestic economic health.

Key Takeaways

  • The LSE is one of the world’s oldest exchanges, now fully electronic and part of LSEG.
  • The FTSE 100 tracks the 100 largest UK-listed companies; the FTSE 250 better reflects the domestic economy.
  • AIM provides a lighter-regulation market for growth companies — a unique feature among major exchanges.
  • London’s time zone overlaps with Asia and the U.S., making it a global trading hub.
  • LSEG also owns Refinitiv (data) and FTSE Russell (indices), making it a diversified market infrastructure group.

Frequently Asked Questions

What is the London Stock Exchange?

The London Stock Exchange (LSE) is one of the world’s largest and oldest stock exchanges. Based in London, it lists over 2,000 companies and operates the Main Market for large-cap stocks and AIM for smaller growth companies. It is part of the London Stock Exchange Group (LSEG).

What are the LSE trading hours?

The LSE is open from 8:00 AM to 4:30 PM Greenwich Mean Time (GMT). For U.S.-based investors, that translates to 3:00 AM to 11:30 AM Eastern Time. Pre-market auctions begin at 7:50 AM GMT.

What is the FTSE 100?

The FTSE 100 (Financial Times Stock Exchange 100) is the LSE’s flagship index, tracking the 100 largest companies listed on the exchange by market capitalization. It includes global giants like Shell, AstraZeneca, and HSBC.

Can U.S. investors trade on the London Stock Exchange?

Yes. U.S. investors can access LSE-listed stocks through international brokerage accounts, or through American Depositary Receipts (ADRs) listed on U.S. exchanges. Many large UK companies trade as ADRs on the NYSE or Nasdaq.

What is AIM on the London Stock Exchange?

AIM (Alternative Investment Market) is the LSE’s growth market for smaller companies. It has lighter listing requirements than the Main Market, making it attractive for startups and expanding businesses. AIM has helped over 3,800 companies raise capital since its launch in 1995.