What is a FIRE portfolio?

A FIRE portfolio is a collection of investments designed to generate sufficient passive income (or support systematic withdrawals) to cover living expenses without needing to work. In the UK, a FIRE portfolio typically spans a pension, a Stocks and Shares ISA, and sometimes a General Investment Account (GIA). The goal is tax efficiency during both the accumulation phase and the drawdown phase.

Should I prioritise my ISA or pension for FIRE?

Both. Pensions offer upfront tax relief (20%–45% depending on your rate) but are locked away until 57 (from 2028). ISAs offer no upfront relief but are flexible and accessible at any time. For FIRE, you typically need both: the pension to cover retirement from 57 onwards (where the tax relief makes it more efficient), and the ISA to bridge the gap between early retirement and pension access age. Max your pension contributions first if you are a higher rate taxpayer; otherwise split between the two.

What index funds should I use for a FIRE portfolio?

Most UK FIRE investors use a simple 2–3 fund portfolio: a global equity index fund (e.g. Vanguard FTSE All-World, iShares MSCI World), a UK equity index fund (optional, for home currency bias), and a bond index fund (e.g. Vanguard UK Gilt or Global Bond). Global equity covers 3,000–9,000 companies across developed and emerging markets. Low ongoing charges figure (OCF) — ideally under 0.20% — preserves more return.

What is a bond tent and why does it matter for FIRE?

A bond tent is the practice of increasing your bond allocation in the years around your retirement date (5 years before to 5 years after) and then gradually shifting back to equities in later retirement. It protects against sequence-of-returns risk — the danger that a major market fall in the first 5–10 years of retirement permanently damages your portfolio. The bond tent provides a stable asset to sell from in bad years, avoiding forced equity selling at depressed prices.

How much cash buffer should I hold in a FIRE portfolio?

A 2–3 year cash buffer (in a high-interest savings account) is the most common approach. This means holding 2–3 years of living expenses in cash outside the main portfolio. If markets fall, you live off cash for 2–3 years and allow the equity portfolio to recover. A £30,000/year budget = £60,000–£90,000 cash buffer. This eliminates the need to sell equities during the most dangerous early-retirement period.

How to Build a FIRE Portfolio in the UK

Building a FIRE portfolio in the UK involves three decisions that most investment guidance ignores: how to split money across different account types for tax efficiency, how to structure withdrawals without paying unnecessary tax, and how to survive a market crash in the first five years of retirement without running out of money. This guide addresses all three.

For the broader early retirement planning framework, return to the Early Retirement hub.

The UK FIRE Account Structure

The UK tax system gives you several sheltered account types. Using them in the right order dramatically reduces the tax paid both during accumulation and in drawdown.

Account type	Tax on contributions	Tax on growth	Tax on withdrawals	Access
Pension (SIPP/workplace)	Tax-relieved (20–45% added back)	Tax-free	Income tax applies	From 57 (2028)
Stocks and Shares ISA	After-tax contributions	Tax-free	Tax-free	Anytime
General Investment Account (GIA)	After-tax	Taxed (CGT/dividend tax)	CGT on gains	Anytime

The priority order for FIRE accumulation:

Pension (if higher rate taxpayer — 40% tax relief is hard to beat)
ISA (especially if basic rate taxpayer or if you need pre-57 access)
GIA (once pension and ISA allowances are exhausted; less tax-efficient)

The ISA Bridge: Funding the Gap Before 57

A critical FIRE planning issue is the gap between early retirement and pension access age (57 from 2028). If you retire at 45, you have a 12-year period where you cannot access your pension.

The ISA bridge is the pool of ISA savings built up to cover this period. Calculate the ISA bridge needed:

ISA bridge = Annual expenses × years until pension access

For a 45-year-old with £25,000/year expenses targeting pension access at 57: £25,000 × 12 = £300,000 required in ISA (in today’s money, before investment returns)

This ISA bridge fund can be held in equities for growth if retirement is still 5+ years away. In the 5 years approaching early retirement, progressively shift ISA assets toward bonds and cash to protect the bridge.

The FIRE Portfolio Structure

Simple 3-Fund Portfolio (Recommended Starting Point)

Fund	Allocation	Purpose
Global equity index (e.g. Vanguard FTSE All-World)	60–80%	Core long-term growth
UK equity index (e.g. iShares FTSE 100)	0–10% (optional)	Home currency tilt
Bond index (e.g. Vanguard Global Bond)	15–30%	Volatility reduction, rebalancing buffer

Keep OCF low. A 1% annual charge versus 0.15% costs tens of thousands of pounds over a 25-year accumulation period. Use index funds, not actively managed funds.

Platform Selection

Platform	Best for	Notes
Vanguard UK	Simple, low-cost	0.15% platform fee (capped at £375/year)
InvestEngine	ISA and GIA only, very low cost	Commission-free ETFs
AJ Bell / Hargreaves Lansdown	Full service	Higher fees; better for large portfolios
SIPP via any FCA-regulated provider	Pension	Ensure FSCS protection

Sequence-of-Returns Risk and the Bond Tent

The greatest threat to a FIRE portfolio is not average returns — it is the sequence of those returns. A 30% market crash in year 1 of retirement, combined with withdrawals of £30,000/year, can permanently impair a portfolio that would otherwise have lasted decades.

The Bond Tent Strategy

Years before/after retirement	Equity allocation	Bond + cash allocation
10 years before	90%	10%
5 years before	80%	20%
Retirement year	60–70%	30–40%
5 years into retirement	70%	30%
10 years into retirement	80%	20%
20 years into retirement	90%	10%

The bond tent rises going into retirement, then gradually unwinds as the early sequence-of-returns risk period passes. In good years, sell equities and rebalance back to bonds. In bad years, sell bonds and leave equities to recover.

The 2–3 Year Cash Buffer

Hold 2–3 years of living expenses in cash (high-interest savings account or Premium Bonds) completely separately from the invested portfolio. In a market crash:

Live off cash for up to 3 years
Allow equity portfolio to recover without forced selling
Once markets recover, replenish the cash buffer from portfolio gains

Drawdown Tax Efficiency

During drawdown, the goal is to generate your spending target from the lowest-taxed sources:

£12,570 personal allowance: Take this much from pension drawdown tax-free each year
Basic rate band (up to £50,270): Additional pension drawdown at 20% tax
ISA withdrawals: Fully tax-free; use to supplement pension drawdown above the personal allowance
GIA gains: Realise up to £3,000 CGT allowance each year tax-free

For couples, each person’s allowances effectively double the available tax-free and basic rate income.

Annual Rebalancing

Rebalance the portfolio annually — or when any asset class deviates more than 5–10% from its target allocation. Sell the outperforming asset, buy the underperforming one. In tax-sheltered accounts (ISA, pension), rebalancing has no tax consequences. In a GIA, rebalancing may trigger CGT — stay within the £3,000 annual exempt amount where possible.