A 3-Fund Halal ISA Portfolio: Sample £20,000 Allocation With Sukuk for Stability
A simple, fully Shariah-compliant three-fund ISA portfolio uses one global equity fund, one emerging-market equity fund, and one sukuk fund in place of the conventional bond sleeve. On a £20,000 stocks & shares ISA, an 80/20 equity/sukuk split puts roughly £16,000 in shares and £4,000 in sukuk for stability — all of it growing free of UK Income Tax and Capital Gains Tax, with rebalancing inside the wrapper triggering no tax event at all.
If you want a halal version of the classic "three-fund portfolio," the only real swap you need to make is at the defensive end. A conventional portfolio holds bonds — and bonds pay interest (riba), which makes them impermissible. The Shariah-compliant equivalent is a sukuk fund: sukuk are asset-backed certificates that distribute profit from real assets rather than interest on a loan. Get that one swap right, wrap the whole thing in a stocks & shares ISA, and you have a clean, low-cost, diversified portfolio you can run for decades.
This guide builds that portfolio from scratch on a sample £20,000 ISA. We cover the exact fund split, why sukuk replaces bonds, how to rebalance without a tax bill, two risk profiles (80/20 vs 60/40), and what the whole thing costs once you blend the fund fees.
The three funds and why each one earns its place
A three-fund portfolio deliberately keeps things minimal. More funds means more overlap, more fees, and more decisions — without meaningfully more diversification. Here are the three roles you are filling:
1. Global equity (developed markets) — the engine
This is the core growth holding: a broadly diversified fund of Shariah-screened companies across the US, UK, Europe and Japan. Look for a fund tracking an Islamic global index (for example, an index based on the S&P 500 Shariah or FTSE Shariah Developed methodology). These screen out companies in alcohol, gambling, conventional banking, tobacco, weapons and adult entertainment, and apply financial-ratio screens (debt and interest-income limits). It typically carries an income-purification estimate so you can cleanse any small impermissible income.
2. Emerging-market equity — the diversifier
Developed-market funds are heavily weighted to US tech. A Shariah-screened emerging-markets fund adds exposure to India, the Gulf, Southeast Asia and other faster-growing economies that the global fund underweights. It is more volatile, so it stays a satellite holding — a slice, not the core.
3. Sukuk — the halal alternative to a bond sleeve
This is the part that makes the portfolio Shariah-compliant where a conventional one would not be. Instead of a gilt or corporate-bond fund (which pay interest), you hold a sukuk fund. Sukuk represent fractional ownership in tangible, income-producing assets — the holder receives a share of the asset's profit or rent, structured to comply with AAOIFI standards, not a guaranteed interest coupon. The practical job is the same one bonds do in a conventional portfolio: dampen volatility and give you something stable to sell from when you rebalance.
Worked example: the 80/20 portfolio on £20,000
Aisha, 34, fills her full ISA allowance. She has £20,000 to invest for the long term (15+ years) and is comfortable with stock-market swings, so she chooses the growth-tilted 80/20 split — 80% equities, 20% sukuk.
Within the 80% equity sleeve she wants a 65/15 tilt toward developed markets over emerging markets. Here is how she divides the £20,000:
- Global (developed) equity — 65%: £20,000 × 0.65 = £13,000
- Emerging-market equity — 15%: £20,000 × 0.15 = £3,000
- Sukuk — 20%: £20,000 × 0.20 = £4,000
Total equities = £13,000 + £3,000 = £16,000 (80%). Defensive sukuk = £4,000 (20%). She places all three buy orders inside her stocks & shares ISA, so every penny of future growth and distribution is tax-free and never appears on a tax return.
The table below shows the same 80/20 build, plus the more cautious 60/40 version for comparison.
Two risk profiles: 80/20 vs 60/40 on £20,000
| Fund (role) | 80/20 — growth | 80/20 on £20k | 60/40 — balanced | 60/40 on £20k |
|---|---|---|---|---|
| Global developed equity | 65% | £13,000 | 48% | £9,600 |
| Emerging-market equity | 15% | £3,000 | 12% | £2,400 |
| Sukuk (defensive) | 20% | £4,000 | 40% | £8,000 |
| Total equity / sukuk | 80% / 20% | £16,000 / £4,000 | 60% / 40% | £12,000 / £8,000 |
Which to choose? The split is a question of time horizon and stomach, not religion — both are equally halal. Use the 80/20 if you are investing for 10+ years and can ride out a 30%+ paper drawdown without selling. Step toward 60/40 if your horizon is shorter (say 5–10 years), if you would lose sleep over big swings, or as you approach the point of drawing on the money. Many investors start at 80/20 in their 30s and glide toward 60/40 as they get older — the larger sukuk sleeve cushions the ride.
Rebalancing inside an ISA — without triggering a tax event
Over time your allocation drifts. A strong equity run might push Aisha's 80/20 portfolio to 86/14. Rebalancing means trimming what has grown and topping up what has lagged to get back to target. In a taxable general investment account, selling the over-grown equity fund could realise a capital gain — and the UK Capital Gains Tax annual exempt amount is only £3,000 for individuals, after which gains are taxed (gov.uk — Capital Gains Tax allowances). That is the friction that puts many people off rebalancing.
Inside an ISA, that friction disappears. Gov.uk is explicit: there is no UK Income Tax or Capital Gains Tax on investments held in an ISA, and you do not declare any ISA income or gains on a tax return (gov.uk — How ISAs work). So you can sell your over-weight equity fund and buy more sukuk inside the wrapper as often as you like, with zero tax consequence on the gain.
Rebalancing Aisha's portfolio a year later. Suppose her £20,000 has grown to £22,000 and equities ran hot, so the split is now 86% equity (£18,920) / 14% sukuk (£3,080). Her target is 80/20.
- Target sukuk = £22,000 × 0.20 = £4,400. She currently holds £3,080, so she is £1,320 short.
- She sells £1,320 of her equity funds (split across global and EM to keep their 65/15 ratio) and buys £1,320 of the sukuk fund — all inside the ISA.
- Result: £17,600 equity (80%) / £4,400 sukuk (20%), back on target.
The key point: that £1,320 of equity she sold included a realised gain. In a taxable account that gain would count toward her £3,000 CGT allowance. Inside the ISA it is invisible to HMRC — no tax, no paperwork, no allowance used up. The one caution: selling and rebuying within the ISA is fine, but withdrawing cash out of the ISA uses up that slice of your £20,000 annual allowance. Rebalance by trading inside the wrapper, not by withdrawing and re-depositing.
A practical rebalancing rule
You do not need to rebalance constantly. A sensible rule: check once a year, and only act if any holding has drifted more than 5 percentage points from its target (an "5/25 band"). Less trading means fewer spread costs and less temptation to tinker. Because there is no tax cost inside the ISA, the only reason to wait is to keep dealing costs and effort down.
What it costs: the blended TER on £20,000
Your ongoing cost is the weighted average of each fund's Total Expense Ratio (TER), weighted by how much you hold in it. Shariah-screened funds historically carried a small premium over the cheapest conventional trackers, though competition has narrowed the gap. The figures below are illustrative TERs in a realistic range for UK-available halal funds — check the latest Key Investor Information Document (KIID) for the exact figure before you buy.
| Fund | Weight (80/20) | Illustrative TER | Weighted cost |
|---|---|---|---|
| Global developed equity | 65% | 0.30% | 0.195% |
| Emerging-market equity | 15% | 0.55% | 0.0825% |
| Sukuk fund | 20% | 0.40% | 0.080% |
| Blended portfolio TER | 100% | — | ≈ 0.36% |
The fund cost on Aisha's £20,000. Blended TER ≈ 0.36%. Annual fund charge = £20,000 × 0.0036 = £72 per year, or about £6 a month, deducted automatically inside the funds.
Don't forget the platform. On top of fund TER, your ISA provider charges a platform fee — typically a percentage fee (often capped) or a flat monthly fee. On £20,000, a 0.25% percentage platform fee = £50/year; a flat-fee platform might charge £0 to £120/year depending on the provider. So Aisha's realistic all-in cost is roughly £72 (funds) + £50 (platform) ≈ £122/year, about 0.61%. Compare platform fee structures: percentage fees suit smaller pots; flat fees win as your balance grows.
- Three funds, one swap: global equity + emerging-market equity + sukuk (not bonds) is a complete, Shariah-compliant version of the classic three-fund portfolio.
- £20,000 ISA allowance (2026/27) across all ISAs combined; growth and income inside a stocks & shares ISA are free of UK Income Tax and CGT and need no tax-return declaration.
- 80/20 on £20k: £13,000 global equity / £3,000 EM equity / £4,000 sukuk. 60/40: £9,600 / £2,400 / £8,000. Pick by time horizon and risk tolerance — both are equally halal.
- Rebalance inside the wrapper: selling and rebuying within an ISA triggers no CGT (the UK CGT allowance is only £3,000 outside an ISA). Never rebalance by withdrawing — that wastes your annual allowance.
- Blended TER ≈ 0.36% on the 80/20 build = about £72/year on £20k; add a platform fee (~£50 on a 0.25% platform) for a realistic all-in cost near £122/year.
- Avoid off-the-shelf "balanced" funds — their defensive sleeve is almost always conventional bonds, which breaks compliance.
Frequently asked questions
Is a stocks and shares ISA itself halal?
The ISA is just a tax wrapper — it is neither halal nor haram on its own. What matters is what you hold inside it. Fill it with Shariah-screened equity funds and a sukuk fund and the contents are compliant. Avoid cash ISAs that pay interest, and avoid conventional bond, gilt or money-market funds inside the wrapper.
Why use sukuk instead of bonds?
Conventional bonds pay interest (riba), which is impermissible in Islamic finance. Sukuk are asset-backed certificates representing ownership in real, income-producing assets, so the holder receives a share of profit or rent rather than interest. They play the same portfolio role bonds do — reducing volatility and giving you a stable sleeve to rebalance from — while remaining Shariah-compliant.
Will rebalancing my ISA cost me tax?
No. Gov.uk confirms there is no Income Tax or Capital Gains Tax on investments inside an ISA, and you do not declare ISA income or gains on a tax return (gov.uk). You can buy and sell within the wrapper freely. The only thing to avoid is withdrawing cash to rebalance, which uses up part of your £20,000 annual allowance.
Should I pick 80/20 or 60/40?
Both are equally permissible — the choice is purely about risk. Choose 80/20 for a long horizon (10+ years) and a higher tolerance for swings; choose 60/40 if your horizon is shorter or you want a smoother ride. The larger sukuk sleeve in the 60/40 version cushions market falls but lowers expected long-run growth.
Do I still owe Zakat on a halal ISA portfolio?
Yes. The ISA is tax-efficient for UK tax purposes, but Zakat is a separate religious obligation calculated on your wealth. Most scholars treat investment holdings held for long-term growth on the basis of their market value (often with adjustments) once your Zakat year passes and you are above the nisab threshold. See our dedicated Zakat worked examples for the calculation.
How much income do I need to purify?
Even well-screened Shariah funds may earn a tiny amount of impermissible income (for example, incidental interest on cash). Reputable Islamic index funds publish an annual purification ratio so you can donate that small portion to charity. Check your fund's factsheet for its stated cleansing estimate.
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