Retirement Portfolio Decumulation: How to Withdraw Without Running Out of Money

The Problem Nobody Teaches You

Roberto is sixty-five years old. He patiently built an ETF portfolio over twenty years of work, reaching 400,000 euros. His state pension (INPS) will provide 1,100 euros per month. To maintain his current lifestyle, he needs 2,500 euros: the gap is 1,400 euros per month, which is 16,800 euros per year to withdraw from the portfolio.

He knows the 4% rule says he can withdraw 4% of his initial wealth each year without exhausting the portfolio over thirty years. Four percent of 400,000 euros is 16,000 euros: close to what he needs. But the 4% rule does not tell him which ETFs to sell first, in what order to draw from different tax-advantaged accounts, or what to do if markets fall 30% in his first year of retirement.

This is the decumulation problem. Knowing how large the portfolio is does not solve it. You need to know how to convert accumulated wealth into a sustainable income stream for thirty years, in a country where ETF capital gains are taxed at 26% and the public pension system delivers less to younger generations with every passing year.

Accumulation and Decumulation: Two Phases with Opposite Logic

During accumulation the goal is straightforward: maximize expected return over the long run, accepting volatility as a manageable inconvenience. A 40% portfolio drop at forty is unpleasant but irrelevant for someone who does not need to liquidate anything.

Decumulation reverses this logic. A 40% drop at sixty-six, in the first year of retirement, can destroy the sustainability of a withdrawal plan even if markets fully recover within five years. The reason is sequence-of-returns risk: selling ETF units during a downturn permanently crystallizes losses, reducing the capital base on which future recoveries will compound.

Historical data on global equity indices shows that an investor who retires just before a prolonged bear market risks exhausting their portfolio decades earlier than one who starts with the same withdrawal plan in a favorable market environment, even if long-run averages are identical. The sequence of years is what matters.

The 4% Rule: Starting Point, Not the Full Answer

The 4% rule comes from the American Trinity Study of 1998, which analyzed 60/40 (stocks and bonds) portfolios over thirty-year periods in US market history. The finding: an initial withdrawal of 4% of portfolio value, adjusted upward for inflation each year, produced a success rate above 95% across all historical thirty-year windows.

For an Italian investor, three important corrections apply.

First, the historical dataset is American. European equity markets have a shorter history and include extended stagnation periods that reduce historical success rates compared to US-only calculations.

Second, there is the tax impact. In Italy, capital gains realized on ETF sales are taxed at 26%. To receive 16,800 euros net, Roberto must sell more than that amount whenever the sale generates capital gains. If 40% of the portfolio value represents unrealized gains, the gross withdrawal required is:

$$W_{\text{gross}} = \frac{W_{\text{net}}}{1 - t \cdot g} = \frac{16{,}800}{1 - 0.26 \times 0.40} \approx \frac{16{,}800}{0.896} \approx 18{,}750 \text{ euros}$$

Where $t = 0.26$ is the capital gains tax rate and $g = 0.40$ is the gain ratio on the amount sold. The effective withdrawal rate on the portfolio is therefore higher than the nominal 4%.

Third, life expectancy matters. With Italian life expectancy well into the eighties for today’s retirees, a thirty-five-year horizon is realistic for someone retiring at sixty-five. A rate of 3.5% is generally considered more prudent for that extended horizon.

Four Withdrawal Strategies Compared

Fixed percentage withdrawal

Withdraw a fixed percentage of the current portfolio value each year, typically 3.5-4%. Income varies: when the portfolio grows the withdrawal increases; when it falls the withdrawal automatically decreases.

The main advantage is mathematical permanence: the portfolio can never be exhausted, since you always draw a share of what remains. The drawback is income unpredictability: a 30% market decline reduces your income by 30% in the same year, with direct consequences for your budget.

Fixed amount withdrawal

Withdraw the same nominal amount each year, possibly adjusted upward for inflation. Cash flow is predictable and simplifies expense planning.

The risk: when markets are unfavorable in the early retirement years, the capital base erodes quickly because the fixed withdrawal does not shrink with portfolio losses. Among the four strategies, this carries the highest risk of portfolio exhaustion.

Dynamic withdrawal

Combines a fixed base with a variable component adjusted to portfolio performance: increase withdrawals by 5-10% in positive years, reduce them by the same amount in negative years. This balances cash flow predictability with the ability to adapt to market conditions.

Bucket strategy

Best suited to those who want to explicitly manage sequence-of-returns risk without being forced to sell equities during downturns. Described in detail below.

The Bucket Strategy: Three Compartments, One Plan

The core idea: divide the portfolio into three time-based compartments with different instruments, so that short-term withdrawals never depend on equity market performance.

Bucket 1 (years 0-3): cash for current expenses. Holds 2-3 years of net withdrawals in zero or near-zero-risk instruments: instant-access savings accounts, short-term government bonds, money market funds. For Roberto, at 1,400 euros per month from the portfolio, this means approximately 34,000-50,000 euros kept completely safe regardless of market conditions.

Bucket 2 (years 3-7): medium-term income. Government bonds maturing in three to seven years, or a short-to-medium duration bond ETF. This compartment generates a return sufficient to preserve purchasing power without exposing capital to equity volatility. As Bucket 1 is drawn down, it is replenished from Bucket 2.

Bucket 3 (beyond 7 years): long-term growth. Global equity ETFs, the portfolio’s return engine. This compartment is never touched while markets are unfavorable. Its function is to grow enough over time to periodically replenish Bucket 2, which in turn replenishes Bucket 1.

The practical benefit is immediate. Roberto knows the next three years of expenses are already safe in Bucket 1. When the market falls 20%, he does not need to sell anything: current expenses are covered, and Bucket 3 has years ahead to recover before it is needed.

Rebalancing between buckets: typically once a year, in good market years, sell a portion of Bucket 3 to top up Bucket 2, then use Bucket 2 to refill Bucket 1. In very bad market years, wait without selling, using Bucket 1 as a buffer. Bucket 3 is never liquidated in adverse conditions.

Tax Sequencing: The Order of Withdrawals Matters

An aspect many decumulation plans overlook: not all sources of portfolio income are taxed equally in Italy.

ETF portfolio (taxable account): capital gains realized on sales are taxed at 26% as capital income (redditi di capitale). Each withdrawal with unrealized gains has a tax cost that reduces the net amount available.

Supplementary pension fund (fondo pensione): benefits paid as income or lump-sum withdrawals are taxed as ordinary income at a preferential initial rate of 15%, which falls by 0.3 percentage points for each year of participation beyond the fifteenth, to a minimum of 9% after thirty-five years. Long-term fund participants have a substantially more favorable tax treatment compared to the 26% rate on ETF gains.

Sequencing logic: in the early years of retirement, when the pension fund rate is still relatively high (near 15%), it is more tax-efficient to withdraw primarily from the ETF portfolio, allowing the pension fund to accumulate additional years of rate reduction. As retirement progresses, the supplementary pension fund becomes progressively more advantageous.

The practical rule for those holding both instruments: draw from the ETF portfolio in the early retirement years, then gradually shift to the pension fund in the second half of the retirement horizon.

The State Pension as an Implicit Bond

A useful way to read Roberto’s situation: the INPS pension is, for all practical purposes, a fixed-coupon bond partially indexed to inflation, issued by the Italian state, that pays every month for life. Capitalizing 1,100 euros per month over thirty years at a modest real rate, the equivalent capital value is between 220,000 and 280,000 euros.

This reframes the overall portfolio picture. Roberto does not have “only” 400,000 euros in ETFs: he has 400,000 euros in ETFs plus an implicit bond worth approximately 250,000 euros. The total portfolio is considerably more balanced than the brokerage statement alone suggests.

The practical consequence: he can hold Bucket 3 with a higher equity allocation than he would choose without the state pension, because the fixed-income component is already provided by INPS. The pension effectively becomes the bond allocation of the overall portfolio, freeing room for growth in the invested portion.

Monitoring the Decumulation Plan

A decumulation plan is not a set-and-forget decision. It should be reviewed at least once a year to confirm the portfolio remains on track.

Wallible’s Monte Carlo simulation lets you input the current portfolio value, the expected annual withdrawal, the time horizon, and the asset class mix, and produces the probability distribution of outcomes across that horizon. A success probability above 90%, meaning the portfolio survives to the end of the horizon in 90% of simulated paths, is generally considered an acceptable margin for retirement planning.

If a bad market year pushes the success probability below 75-80%, that is the signal to act: temporarily reduce withdrawals, defer a major expense, or rebalance the buckets earlier than planned. The simulation does not predict the future, but it quantifies the impact of each choice in a structured way.

FAQ

What is portfolio decumulation?

Portfolio decumulation is the phase where you draw down accumulated investments to fund living expenses in retirement, as opposed to the accumulation phase where you build wealth. It requires managing withdrawal rate, tax sequencing, and sequence-of-returns risk in ways that accumulation does not.

How much capital do you need to retire with ETFs in Italy?

The required capital depends on the gap between your public pension and monthly expenses. With a 1,000 euro monthly gap and a 3.5% withdrawal rate, you need around 343,000 euros. With a 2,000 euro monthly gap, the capital rises to approximately 686,000 euros. The longer your expected retirement horizon, the more conservative the withdrawal rate should be.

What happens if markets crash 40% right after I retire?

This is the heart of sequence-of-returns risk. With the bucket strategy, the first three years of expenses are safe in Bucket 1 and do not depend on market performance. If the downturn extends beyond three years, you draw from Bucket 2 (bonds), while Bucket 3 still has time to recover before being liquidated. In historically very severe scenarios, temporarily cutting withdrawals by 10-15% is the most effective adjustment.

Should I withdraw from the pension fund or ETFs first?

Generally, withdraw from the ETF portfolio first in the early retirement years, when the pension fund tax rate is still near 15%. As years of fund participation accumulate, the rate falls toward a minimum of 9%, making the fund increasingly attractive as a source of income later in retirement.

Is the INPS state pension guaranteed?

Benefits already accrued are constitutionally protected and cannot be reduced retroactively. Future reforms affect access requirements and calculation methods for those who have not yet reached the qualifying thresholds. A prudent decumulation plan accounts for a scenario where inflation indexation of the pension is below expectations, as has occurred in some periods under Italian pension law.

Next Step

The decumulation phase is the most consequential in an investor’s financial life. A plan built before retirement, reviewed annually, and adapted to market conditions is what separates a portfolio that lasts from one that runs dry at the wrong moment.

With Wallible you can:

• Simulate the sustainability of your withdrawal plan with Monte Carlo: input your current portfolio, expected annual withdrawal, and time horizon, and see the probability distribution of outcomes
• Read the article on sequence-of-returns risk to understand why the early retirement years are the most critical for portfolio durability
• Study the 4% rule to understand the historical basis of the withdrawal rate and its limitations for Italian investors
• Review how ETF taxation in Italy affects net withdrawals and plan the optimal tax sequencing with your accountant