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The Cheapest Stocks & Shares ISA by Portfolio Size (2026)

Which UK investment platform costs the least for your portfolio? A full breakdown from £10,000 to £500,000 across all nine major platforms.

Updated 6 June 2026 · 6 min read

Platform fees have a larger impact on long-term returns than most investors realise. At 0.35% on a £100,000 portfolio, you’re paying £350/year — money that could be compounding for you instead. Over 20 years, the difference between paying £0 and £350/year on a £100,000 portfolio is significant.

Here’s a full breakdown of costs at each portfolio size, based on published fees as of June 2026.

The full cost table

Annual cost for an ISA invested in funds, with monthly trading (12 trades/year).

PortfolioBarclaysFreetradeVanguardii CoreHLAJ BellFidelity
£10,000£0£0£48£120£58£43£35
£25,000£0£0£48£120£111£81£88
£50,000£0£0£75£120£198£143£175
£100,000£0£0£150£120£373£268£350
£250,000£0£0£375£120£898£643£875
£500,000£0£0£375£120†£1,523£1,268£1,375

†ii Core plan is limited to portfolios up to £100,000. Above that, the Plus plan (£179.88/year + £1.49/trade) is required. InvestEngine (£0, ETFs only) and Trading 212 (£0, ETFs and shares) not shown as they don’t offer funds.

Figures include platform fees and dealing charges for 12 trades/year. Verify all fees directly with providers before investing.

Use our fee calculator for your exact figures across ETFs, shares, and different trading frequencies.

The new standout: Barclays for fund investors

In June 2026, Barclays Smart Investor removed its platform fee and charges nothing to buy or sell funds. For a fund investor — someone buying unit trusts or OEICs — this makes Barclays uniquely free at any portfolio size.

Previously, the only zero-cost platforms (InvestEngine, Trading 212, Freetrade) were limited to ETFs and shares. Barclays is the first major platform to offer a complete fund range at zero cost.

The trade-off: ETF and share dealing costs £6 per trade. For frequent ETF traders, the free platforms remain cheaper.

Under £30,000 in funds

Cheapest: Barclays (£0) or Freetrade (£0)

Barclays and Freetrade both charge nothing. For funds specifically, Barclays is the only free option. Fidelity at 0.35% is the next cheapest percentage platform (£35 on £10,000).

Vanguard now charges a minimum of £48/year for portfolios under £32,000 — its flat £4/month minimum fee makes it less competitive at this size than previously.

£30,000–£80,000

Cheapest for funds: Barclays (£0) — but ii Core (≈£120/year) is the cheapest full-range paid platform

The old answer here was Vanguard. That’s changed: Vanguard now costs £48–£120/year in this range, and Barclays costs £0. ii Core at ≈£120/year offers the broadest investment range of any paid platform at a flat cost.

£80,000–£100,000

Cheapest full-range paid option: ii Core (≈£120/year)

At £100,000, ii Core costs approximately £120/year while Vanguard reaches £150/year. HL costs £373/year. Above £100,000, you’d need to upgrade to ii Plus at £179.88/year — making Vanguard cheaper again for investors between £100k and £250k who can accept Vanguard’s fund-only range.

£100,000–£250,000

Cheapest with full range (ignoring Barclays): ii Plus at £179.88/year

Barclays is free for funds at any portfolio size. For investors wanting the full market (shares, investment trusts, bonds), ii Plus at £179.88/year is the most competitive flat-fee option. HL costs £898/year at £250,000.

Over £250,000

Cheapest full range: ii Plus (£179.88/year)

At £250,000, Vanguard’s 0.15% hits its annual cap of £375/year. ii Plus stays at £179.88. HL charges £898. The case for a flat-fee platform is overwhelming at large portfolio sizes.

The ETF picture is different

The table above is for fund investors. ETF investors have a completely different cost profile:

PlatformETF annual fee (ISA, 12 trades/year)Notes
InvestEngine£0ETFs only
Trading 212£0ETFs and shares
Freetrade£0ETFs, shares, and now funds
AJ Bell£42 cap + dealing£5/trade, but cap limits total
HL£150 cap + £6.95/tradeCap raised from £45 in March 2026
Barclays£72 (12 × £6)No annual cap, £6/trade
Vanguard£48 minimum + 0.15%ETFs only from Vanguard’s range

For ETF investors, InvestEngine, Trading 212, and Freetrade are all free. HL’s ETF cap rose to £150/year in March 2026 — making it considerably less competitive for ETF-only investors than it was.

What “free” platforms give up

For the genuinely free platforms:


Fee estimates based on published rates as of June 2026. Figures include platform fees and dealing charges for monthly trading. Always verify current fees directly with your provider.