How to Choose a UK Investment Platform: The Costs That Actually Matter
Last reviewed: June 2026 | Sources: FCA, FSCS, platform fee schedules
TL;DR
- UK investment platforms charge either a percentage of assets under management (typically 0.15% to 0.45% per year) or a flat fee (typically £60 to £250 per year).
- Percentage platforms are cheaper for small portfolios. Flat-fee platforms are cheaper for portfolios above approximately £25,000 to £50,000 depending on the specific platforms compared.
- FSCS protection covers up to £85,000 per authorised firm for investments - but this protects against platform insolvency, not against market falls in the investments themselves.
- Dealing charges, fund switching fees, and exit charges are separate from the platform fee and can significantly increase total costs for active investors.
- FCA authorisation is the minimum standard - verify any platform at register.fca.org.uk before depositing money.
Last reviewed: June 2026
Percentage vs Flat Fee: The Most Important Platform Decision
The fundamental choice in UK investment platform selection is between platforms that charge a percentage of the portfolio value annually and those that charge a flat fee. This choice has a more significant impact on long-term investment outcomes than almost any other platform decision, including fund selection and dealing frequency for passive investors.
A percentage charge of 0.25% on a £10,000 portfolio costs £25 per year. On a £100,000 portfolio, the same percentage charge costs £250 per year. On a £500,000 portfolio, it costs £1,250 per year. A flat fee of £120 per year costs £120 regardless of portfolio size. The crossover point at which the flat fee becomes cheaper than the percentage depends on the specific charges of the platforms being compared, but typically falls between £25,000 and £60,000 for the most common UK platform comparisons.
Over a 25-year accumulation period, the compounding impact of platform fees on a growing portfolio is substantial. An investor accumulating a pension or ISA who remains on a 0.45% percentage platform through the growth phase pays significantly more in platform fees than one who switches to a flat-fee platform as the portfolio grows. FCA analysis of investment platform charges published in 2024 showed that the total cost difference between the most and least expensive platforms for a £100,000 ISA over 20 years exceeded £35,000 for comparable investment strategies.
The Major UK Investment Platforms: A Fee Framework
Hargreaves Lansdown is the largest UK investment platform by assets under administration, with over £140 billion as of 2025. It charges 0.45% per year on the first £250,000 of shares and ETFs (capped at £45 per year per account type for shares and ETFs, but uncapped for funds at 0.45%), with lower tiers above £250,000. Its primary advantages are breadth of available investments, research quality, and customer service track record. Its primary disadvantage is cost relative to alternatives for investors holding primarily low-cost index funds.
Vanguard Investor is the UK platform operated by Vanguard, the index fund provider. It charges 0.15% per year (capped at £375 per year) on ISAs and general accounts, and 0.15% (capped at £375 per year) on SIPPs. It offers only Vanguard funds and ETFs - no third-party funds or individual shares. For investors committed to Vanguard's fund range, particularly the FTSE All-World ETF (VWRP) or Vanguard LifeStrategy funds, it is among the lowest-cost platforms available.
Interactive Investor charges a flat fee rather than a percentage. The Investor plan charges £4.99 per month (£59.88 per year) plus £3.99 per trade for shares and ETFs, with one free trade per month. The Super Investor plan charges £19.99 per month with two free trades per month. For a passive investor making no more than one or two trades per month, Interactive Investor becomes cheaper than Hargreaves Lansdown at approximately £13,000 to £20,000 of portfolio value, and cheaper than Vanguard Investor at approximately £40,000 of portfolio value. It is also available as a joint account, which most major platforms are not.
iWeb is operated by Halifax Share Dealing, a subsidiary of Lloyds Banking Group. It charges a one-off account opening fee of £100 and then £5 per trade, with no ongoing annual fee. For a completely passive investor holding index funds in an ISA and making no trades, the total annual cost after the initial fee is zero. For investors who make infrequent trades, iWeb is the lowest ongoing cost platform for larger portfolios. Its disadvantages are a less polished user interface and fewer research tools than premium platforms.
FSCS Protection: What It Covers and What It Does Not
The Financial Services Compensation Scheme (FSCS) protects clients of FCA-authorised investment platforms up to £85,000 per authorised firm in the event of platform insolvency. This protection covers the cash and investments held on the platform if the platform itself fails - it does not cover losses from market falls in the value of the investments.
The distinction is important and frequently misunderstood. A UK equity index fund that falls 30% in a market downturn is not an FSCS claim - it is a market event. FSCS coverage is relevant only if the platform itself becomes insolvent, in which case it covers the shortfall if client assets cannot be fully returned. Under FCA Client Assets rules (CASS), UK platforms are required to hold client assets separately from their own funds, which means platform insolvency typically does not result in client asset loss - but the FSCS backstop provides additional protection if segregation is inadequate.
For portfolios above £85,000 held on a single platform, spreading across two FCA-authorised platforms provides full FSCS coverage on both portions. The practical importance of this is limited by the CASS protections, but the principle of not concentrating assets above the FSCS limit on a single platform is sound risk management.
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Frequently Asked Questions
Which UK investment platform has the lowest fees?
It depends on portfolio size and trading frequency. For small portfolios under £20,000, Vanguard Investor (0.15%) or Freetrade are typically lowest cost. For portfolios of £40,000 to £100,000, Interactive Investor's flat fee typically undercuts percentage platforms. For large, infrequent-trading portfolios above £100,000, iWeb's £5 per trade with no annual fee is often lowest total cost.
Is Hargreaves Lansdown worth the higher cost?
For simple index fund investors, HL's 0.45% charge is difficult to justify versus lower-cost alternatives for portfolios above approximately £20,000. Its advantages - breadth of investment options, customer service, research tools, and account types including joint accounts and junior ISAs - have genuine value for more complex investment needs. For straightforward index fund ISAs and SIPPs, cost-optimised alternatives typically outperform HL on total return over time.
How does FSCS protect investment platform clients?
FSCS covers up to £85,000 per FCA-authorised firm if the platform itself becomes insolvent and cannot return client assets. It does not protect against investment losses from market falls. Client assets must be held separately from platform assets under FCA CASS rules, which means platform insolvency typically does not result in client asset loss before FSCS involvement.
