Sustainable Withdrawal Rate in Retirement: How Much Can You Safely Spend?

For those approaching or in retirement with a defined contribution pension pot, investment ISA or other accumulated wealth, the fundamental question is how much can be drawn down each year without the risk of exhausting the portfolio before death. This question — deceptively simple in framing, complex in execution — is one of the most consequential decisions in financial planning.

The 4% Rule: Origins and Evidence

The concept of a "safe withdrawal rate" gained prominence through research by US financial planner William Bengen in 1994, who analysed historical US market data and concluded that a portfolio invested in US equities and bonds could sustain annual withdrawals of 4% of the initial portfolio value, indexed for inflation, over a 30-year retirement period, without failing in any historical scenario.

The "4% rule" has become the most widely cited benchmark in retirement income planning. However, it has important limitations for UK and international investors:

US data bias: Bengen's original work used US market returns, which have been among the strongest in the world over the relevant period. Using UK or global market data historically suggests a lower sustainable rate — somewhere between 3% and 3.75% for a 30-year horizon on a globally diversified portfolio.

Sequence of returns risk: the safe withdrawal rate is highly sensitive to the order in which returns occur, not just the average return. A portfolio that experiences severe falls in the first 5 years of retirement is permanently impaired — even if subsequent returns are strong, the depleted capital generates insufficient recovery. A portfolio that experiences strong early returns is much more resilient. This "sequence of returns risk" is the defining risk of the decumulation phase.

Longevity: 30 years was reasonable for a 65-year-old in 1994. A 60-year-old today may need the portfolio to last 35–40 years. The sustainable withdrawal rate over 35 years is lower than over 30 years.

Inflation: the 4% rule indexes withdrawals for inflation. In periods of high inflation (as seen 2021–2023), the real cost of maintaining spending rises rapidly, drawing more from the portfolio in nominal terms.

UK-Specific Considerations

State Pension: the UK State Pension (approximately £12,548 per year for a full new State Pension entitlement in 2026/27, at £241.30/week, triple-locked) is a guaranteed, inflation-linked income that reduces the required withdrawal from the investment portfolio. A couple both receiving the full new State Pension receive approximately £25,096 per year between them — potentially meeting a significant proportion of their basic spending needs without drawing from investments.

The impact on sustainable withdrawal rates is significant: a portfolio that needs to fund the gap between total desired income and the State Pension can sustain a higher percentage withdrawal from the remaining portfolio (which is smaller, but the percentage withdrawal on the gap is what matters for sustainability analysis).

Defined Benefit pensions: where a DB pension is also in payment, the remaining DC portfolio can be managed as a supplementary income source and legacy vehicle rather than as the primary income generator. The calculus is entirely different.

Annuity option: purchasing a lifetime annuity — converting part or all of the DC pot into guaranteed lifetime income — eliminates longevity risk from that portion of assets. The remaining invested portfolio can then be more aggressively positioned. A partial annuity at, say, 75 — when longevity is more uncertain and health may be declining — is a legitimate strategy for the risk-averse.

Revised Sustainable Withdrawal Rate Estimates

Based on research using UK and global data, and accounting for current lower expected real returns compared to the long-run historical averages, broadly:

• 25-year retirement (age 65 to 90): 3.5–4.0% sustainable withdrawal rate (real, indexed for inflation) for a balanced portfolio.
• 30-year retirement (age 60 to 90): 3.0–3.75%.
• 35-year retirement (age 55 to 90): 2.75–3.5%.

These figures are probability-based estimates, not guarantees. They represent the withdrawal rate at which historical scenarios show a high probability of success (typically 90–95% of scenarios not failing). They are sensitive to asset allocation, product charges, and the specific inflation assumption.

Important caveat: every retirement situation is unique. These rates are tools for planning, not rules. Actual sustainable withdrawal rates depend on the specific portfolio, spending patterns, health, other income sources, and willingness to adjust spending. A financial adviser running a proper cashflow model for a specific client will produce a more accurate answer than any general guideline.

Sequencing Risk: The Most Dangerous Phase

The five years immediately before and after retirement are the most critical for long-term portfolio sustainability. A 20–30% market fall in year one of retirement permanently reduces the portfolio from which all future withdrawals are made. Unlike during accumulation — where a fall is an opportunity to buy more at lower prices — in decumulation, a fall combined with ongoing withdrawals locks in losses.

Managing sequence risk:

Cash buffer: holding one to two years of anticipated withdrawals in cash or near-cash (money market funds, short-duration bonds) means market falls do not force selling of equities at depressed prices. Withdrawals come from the cash buffer, which is replenished when markets recover.

Bucket strategy: a three-bucket approach divides the portfolio into: (1) short-term cash for 1–3 years of spending; (2) medium-term bonds and income assets for years 3–10; (3) long-term growth assets for years 10+. Each bucket is replenished from the next over time, insulating short-term spending from long-term volatility.

Flexible spending: reducing discretionary spending in the year following a significant market fall — and allowing the portfolio to recover before resuming the full withdrawal — extends portfolio longevity considerably. Retirees who treat the withdrawal rate as a fixed commitment regardless of market conditions are more exposed to sequencing risk than those who can flex.

The Income vs Total Return Debate

Some retirees prefer to live off income only — dividends, bond coupons, rental income — without ever selling capital. This approach has psychological appeal (the capital never diminishes) but is not necessarily optimal from a total return or tax efficiency perspective.

A portfolio tilted toward high-yield assets to maximise income may sacrifice capital growth and diversification. In a low-yield environment, maintaining a high natural income from a portfolio may require holding concentrated, higher-risk positions.

Total return investing — spending from the portfolio based on a sustainable withdrawal calculation, using both income and strategic capital realisations — is generally the more efficient approach. It allows asset allocation to be optimised for risk and return rather than constrained by yield requirements.

When to Consider Annuitising

An annuity provides guaranteed income for life — eliminating longevity risk entirely from the annuitised portion. The cost is the premium paid and the loss of flexibility.

Arguments for annuitising at 75+:

• Longevity risk becomes more tangible at 75+; the probability of living 25 more years diminishes but is not negligible.
• Cognitive decline means managing a drawdown portfolio becomes more difficult.
• The guaranteed income provides a minimum income floor that is independent of markets.

Arguments against early annuitisation:

• Annuity rates improve with age — deferring an annuity purchase until 75 or 80 generally produces a meaningfully better income for the same premium.
• Flexibility is valuable, particularly for funding care costs or large one-off expenditures.
• If you die early, the capital is lost to the insurer.

A hybrid approach — maintaining a drawdown portfolio for flexibility while purchasing an annuity to cover minimum income needs — balances security with flexibility.

Drawdown vs Annuity: The IHT Consideration

Pension funds held in drawdown remain outside the estate for IHT purposes under current rules (though this is changing for deaths from April 2027, when pensions will be brought within the IHT net). Annuities, once purchased, cease on death (unless a guaranteed period or dependant's annuity is included).

If IHT is a concern and the pension pot is a significant part of the estate, maximising the period of drawdown rather than annuitising keeps assets outside the IHT net — at least under current rules. This consideration will become less relevant once the April 2027 changes take effect.

How Global Investments Can Help

Global Investments builds comprehensive retirement income models for clients approaching and in retirement, using cashflow planning tools that stress-test income against longevity, inflation, and investment scenarios. We advise on the interaction between pension drawdown, ISA spending, property income, State Pension, and other sources. Contact our team to discuss building a retirement income plan tailored to your specific circumstances.