Interactive Investor Fees 2026: Core, Plus, or Premium — The Exact Maths Across £50k, £150k, and £500k

Every ii plan bundles ISA, SIPP, and Trading Account access into one monthly fee. There is no separate pension charge — a structural change from ii's pre-February 2026 pricing that quietly saves SIPP holders up to £156 a year. All numbers are direct from ii's charges page.

Core — £5.99/month (£71.88/year)

• Portfolio limit: up to £100,000 across all accounts
• Fund trades: £3.99 each
• UK/US share and ETF trades: £3.99 each
• Other international shares: £9.99 each
• FX charge: 0.75%
• Regular investing: free
• Dividend reinvestment: £0.99 per holding
• No Junior ISA, no family accounts
• Pension admin fee: £2.50/month inc. VAT (already included in the £5.99)

Plus — £14.99/month (£179.88/year)

• Portfolio limit: none
• Fund trades: £1.49 each
• UK/US share and ETF trades: £3.99 each
• Other international shares: £7.99 each
• FX charge: 0.75% on first £50,000, 0.25% above
• 1 free monthly trade (£3.99 credit applied to any trade)
• 5 free family accounts including Junior ISAs
• Pension admin fee: £6/month inc. VAT (included)

Premium — £39.99/month (£479.88/year)

• Portfolio limit: none
• Fund trades: free
• UK/US share and ETF trades: £2.99 each
• Other international shares: £5.99 each
• FX charge: 0.25% flat
• 2 free monthly trades (£5.98 credit)
• Unlimited free family accounts
• ii360 advanced trading platform (rolling out 2026)

No platform fee scales with your portfolio. No exit fees, no transfer-in fees, no withdrawal fees. The structure is designed for one thing — to undercut percentage-fee rivals at scale — and at scale it succeeds emphatically.

The £50,000 portfolio is the testing ground for whether ii's flat fee actually beats percentage rivals at the size most UK investors realistically reach. Assume the standard retail mix: £40,000 across five funds (typical UK index trackers and global equity funds) and £10,000 across two ETFs. Six trades a year — four fund switches and two ETF top-ups.

Using each platform's published April 2026 charges:

• ii Core: £71.88 platform fee + (6 × £3.99) = £95.82/year
• AJ Bell: £40,000 × 0.25% funds custody = £100 + £10,000 × 0.25% shares custody = £25 + (4 × £1.50 fund deals) + (2 × £5.00 share deals) = £141.00/year (per AJ Bell ISA charges)
• Hargreaves Lansdown: £40,000 × 0.35% funds custody = £140 + £10,000 × 0.35% shares = £35 (under £150 cap) + (4 × £1.95 fund deals) + (2 × £6.95 share deals) = £196.70/year (per the new HL March 2026 pricing)

ii Core wins by £45 a year against AJ Bell and just over £100 against the new HL pricing. Over ten years, assuming static portfolio size, that is £450-£1,000 of compounded fee saving — meaningful, but not transformative.

The gap widens as the funds-to-shares ratio shifts. Pure-funds investors lose more to percentage fees; pure-share investors with HL's new £150 share cap can actually be cheaper at HL than at ii Core. The cap is a real change worth modelling — for a £50,000 portfolio held entirely in ETFs and individual shares, HL's annual cost would be £150 (capped) + £13.90 dealing = £163.90, still slightly more than ii Core but close enough that frequent traders should weigh it carefully.

Flat fees beat percentage fees once portfolios pass critical thresholds. Below those thresholds, percentage-fee platforms cost less. The 2026 fee changes shifted every crossover — here is where each one now sits.

ii Core (£71.88/year) vs AJ Bell (0.25% on funds): breakeven at £28,752. Below that, AJ Bell is cheaper for fund holders. Above, ii Core wins.

ii Core vs HL (0.35% on funds): breakeven at £20,537. Pure-fund holders below this number pay less at HL despite the higher headline rate, because ii Core's £71.88 floor exceeds HL's percentage take. Above, ii pulls ahead.

ii Plus (£179.88/year) vs AJ Bell (0.25% on funds): breakeven at £71,952. Important: this is well below the £100,000 Core ceiling, so the moment ii forces you onto Plus, you are already past the AJ Bell crossover.

ii Plus vs HL (0.35% on funds): breakeven at £51,394. Plus pays back almost immediately for fund-heavy investors over £52,000.

The share-cap inversion: HL's new £150-per-account share cap means that if your ISA holds £42,857+ in shares (where 0.35% × £42,857 = £150), HL ceases to scale on that account. A £200,000 share-only ISA at HL costs £150 + dealing — cheaper than ii Plus's £179.88 plus £3.99 share trades. AJ Bell's £42/year share cap (£3.50/month) creates the same dynamic at an even lower threshold for share-only portfolios.

For our flat-fee vs percentage-fee deep dive covering every scenario, see the full breakdown. The simple rule: ii wins when you hold mostly funds; the percentage platforms with their share caps win when you hold mostly individual shares and ETFs and rarely trade.

Above £100,000 you are forced onto Plus, so the relevant comparison is ii Plus versus the percentage rivals. The flat-fee advantage compounds aggressively at scale.

£150,000 portfolio (£120k funds, £30k shares/ETFs, 6 trades a year):

• ii Plus: £179.88 + (4 × £1.49) + (2 × £3.99) − £47.88 free-trade credits = £145.94/year
• AJ Bell: £120,000 × 0.25% + £30,000 × 0.25% (under £42 cap) + £16 dealing = £391.00/year
• HL: £120,000 × 0.35% + £30,000 × 0.35% (£105, under £150 cap) + £21.70 dealing = £546.70/year

ii Plus saves £245 a year against AJ Bell and £401 against HL.

£500,000 portfolio (£400k funds, £100k shares/ETFs, 6 trades a year):

• ii Plus: still £145.94/year — flat-fee structure does not scale
• AJ Bell: £250,000 × 0.25% + £150,000 × 0.10% (next tier) + £100,000 shares capped at £42 + £16 dealing = £833.00/year
• HL: £400,000 × 0.35% = £1,400 + £100,000 × 0.35% capped at £150 + £21.70 dealing = £1,571.70/year

At £500,000, ii Plus saves £687 a year against AJ Bell and £1,426 against HL. Over a 20-year accumulation period, those savings — ignoring compounding — exceed £13,000 and £28,000 respectively. Reinvested at a 5% real return, the compounded ii-versus-HL gap on a £500k portfolio approaches £50,000.

This is the case for ii at scale. There is no plausible cost argument against ii Plus once you are over £150,000 in funds. The only competing structures — iWeb's £100 one-off fee, Vanguard's 0.15% capped at £375 — either constrain investment choice (iWeb has no ready-made portfolios, Vanguard restricts you to in-house funds) or scale less aggressively than ii's flat structure.

ii is not universally cheapest. Three scenarios where it loses:

Small portfolios (under £20,000) holding mostly funds. £71.88 a year is a 0.36% drag on a £20,000 fund portfolio — higher than HL's 0.35% and AJ Bell's 0.25% custody charges. For an ISA holder building from £5,000-£15,000, Trading 212 (free) or InvestEngine (free for DIY ETF portfolios) are unbeatable. Freetrade's Standard plan at £5.99/month exactly matches ii Core's headline price but limits you to fractional shares with a 0.99% FX spread.

Single-fund or robo-style investors. If you are buying one global tracker and never switching, ii's flat fee is overkill. Vanguard at 0.15% on a £30,000 LifeStrategy holding costs £45 a year — £27 cheaper than ii Core. The Vanguard ceiling of 0.15% capped at £375 means it stays cheap up to £250,000 if you only hold Vanguard funds.

Share-only frequent traders. Premium's £39.99/month with two free monthly trades gives effective dealing of £29.96/month + £2.99 per extra trade. A trader doing 30 share trades a month pays £29.96 + (28 × £2.99) = £113.68/month. The same trades on AJ Bell cost £42 cap + (30 × £3.50 frequent rate) = £147/month. ii Premium wins, but only just — and most retail traders will not hit the 30-trades-a-month frequency that justifies the £39.99 base.

The Core plan's £100,000 ceiling deserves separate attention. Cross the threshold and you are bumped to Plus at £14.99/month with no grace period and no notification timing of your choosing. Market fluctuations create billing unpredictability: a strong month in equities can flip you onto Plus, then a correction back below £100,000 keeps you there until you actively downgrade — with a one-month minimum on the new plan before any further change. An investor near the boundary should plan to be on Plus and treat Core as a temporary discount.

Plus and Premium include free family accounts — a structural feature no UK competitor matches.

On Plus, you get five free family accounts, each with a Stocks & Shares ISA and Trading Account, capped at £100,000 per family member. They pay no monthly fee and trade at Core rates (£3.99 fund, £3.99 UK/US share). On Premium, family accounts are unlimited.

The maths for an investing family with two parents and two adult children: at HL, four ISAs at 0.35% on, say, £50,000 each = £700/year in custody alone. At AJ Bell: 4 × £125 = £500/year. At ii Plus: £179.88/year total — every family account included in the headline fee.

For families targeting Junior ISA growth across multiple children, Plus's free Junior ISAs are worth roughly £36 a year per child (the cost of a JISA on AJ Bell at 0.25% × £20,000 typical balance = £50, on HL at 0.35% × £20,000 = £70). HL has no JISA charges at all currently, but the ii family-bundle structure scales to the parents' accounts in a way HL's standalone JISA does not.

The family feature alone justifies Plus over Core for any investor with adult children planning to fund their own ISAs. It is the most genuinely differentiated piece of ii's pricing — and the easiest to overlook when comparing headline platform fees.

Headline plan fees miss two costs that hit international investors and dividend-focused portfolios hardest.

Foreign exchange: ii Core charges 0.75% on every conversion. A US-share-heavy investor buying $20,000 in dividend stocks and selling later pays 0.75% × $20,000 × 2 = $300 in FX over a single round trip. Plus drops this to 0.75% on the first £50,000 then 0.25%; Premium is a flat 0.25%. Compare with Trading 212's 0.15% spread or InvestEngine's free FX on most ETFs and the gap is material for active US traders.

Dividend reinvestment: Core and Plus charge £0.99 per holding per dividend event. An investor with 20 dividend stocks paying quarterly = 80 events × £0.99 = £79.20/year on top of plan fees. Premium and HL both make dividend reinvestment free. AJ Bell charges £1.50.

For a dividend-focused portfolio, this single cost can flip the platform comparison. A 30-stock UK income portfolio worth £80,000 at ii Core costs £71.88 + (120 × £0.99) = £190.68/year. The same portfolio at HL costs £80,000 × 0.35% = £280 (capped at £150 if all in shares — actual cost £150 + £6.95 dealing = £156.95 for any one trade) plus free dividend reinvestment. HL's share cap inverts the comparison for share-only income portfolios above ~£40,000.

The broader point: ii's headline simplicity hides nuance. Run the numbers on your specific holdings rather than relying on the plan-tier comparison alone. Our cash ISA comparison tool does not yet cover S&S ISAs, but the fee-comparison principle is the same — reach for a calculator before committing.

This article is for informational purposes only and does not constitute financial advice. You should seek independent financial advice from an FCA-authorised adviser before making any investment decisions. Investment platforms charge fees that may change without notice — always verify current pricing on each provider's official charges page before opening or transferring an account. Past performance and current cost differentials are not reliable indicators of future results, and platform pricing structures may change. FSCS investment protection of £85,000 per firm applies to all three platforms covered (Interactive Investor, AJ Bell, Hargreaves Lansdown) — see the FSCS for details. For more on choosing an investment platform, see our investing hub and the MoneyHelper guide to investment platforms.