In the UK, the "Big Three" of retail investing—Hargreaves Lansdown, Interactive Investor, and AJ Bell—continue to hold the largest share of the market, though specialized platforms like IG lead in active trading volume.
1. Hargreaves Lansdown (The Market Leader by Assets)
Hargreaves Lansdown (HL) remains the undisputed heavyweight of the UK investment world. As a FTSE 250 company, it accounts for over 30% of the UK’s direct-to-consumer platform market.
Assets Under Administration (AUA): Over £175 billion.
Client Base: Approximately 2 million active investors.
Why it wins: HL is known for its "Premium Service" model. It offers the most comprehensive research, a highly-rated mobile app, and a vast range of investment options including ISAs, SIPPs, and Junior ISAs.
Best For: Investors who prioritize high-quality customer service, deep market research, and the security of a long-established industry leader.
2. Interactive Investor (The Flat-Fee Champion)
Interactive Investor (ii) is the UK’s second-largest investment platform and is now a key part of the global financial group abrdn.
Market Position: It holds roughly 17% of the market share.
The "Flat Fee" Advantage: Unlike HL, which charges a percentage-based fee on your portfolio, ii charges a fixed monthly subscription fee (starting around £4.99 to £11.99).
Best For: Investors with larger portfolios (typically over £50,000) who want to save thousands of pounds in administration fees over the long term.
3. AJ Bell (Best Value for Mid-Range Investors)
AJ Bell is the third pillar of the UK’s major investment platforms. It has seen rapid growth in 2026 due to its transparent pricing and user-friendly interface.
Assets Under Administration: Exceeding £85 billion.
Why it wins: AJ Bell positions itself as the "middle ground" between HL’s premium service and ii’s flat-fee model. Their percentage-based custody fee is lower than HL’s (capped at 0.25% for shares), making it very attractive for growing portfolios.
Best For: Beginners and intermediate investors looking for a balance between low costs and a robust, easy-to-use platform.
4. IG (The Leader in Active Trading)
While the others focus on long-term investing, IG is the powerhouse for active traders. It is the UK’s largest provider of spread betting and CFDs and has a significant presence in direct share dealing.
Global Scale: A constituent of the FTSE 250 with a massive global footprint.
Why it wins: IG offers access to over 17,000 global markets. In 2026, its "L2 Dealer" platform is considered the gold standard for technical analysis and lightning-fast execution.
Best For: Day traders and sophisticated investors who want to trade international stocks, forex, and commodities with advanced charting tools.
Quick Comparison: UK Brokerage Landscape 2026
| Broker | Primary Model | Main Fee Type | Investor Type |
| Hargreaves Lansdown | Premium/Full Service | Percentage-based | Research-focused |
| Interactive Investor | Value/Fixed Cost | Flat monthly fee | High-net-worth |
| AJ Bell | Efficient/Hybrid | Lower percentage | Balanced/Growth |
| IG | Professional/Active | Commission/Spreads | Active Traders |
Key Protections for UK Investors
When choosing a broker in the UK, ensure they are:
FCA Regulated: The Financial Conduct Authority provides the legal framework for your protection.
FSCS Protected: Under the Financial Services Compensation Scheme, your investments are protected up to £85,000 per person, per firm, if the broker goes bust.