How Much of Your Portfolio Should Be in Bonds? A Decision Framework

“Subtract your age from 100 — that’s your stock allocation.” It’s a clean rule. Easy to remember. And it was a reasonable heuristic in 1972, when average life expectancy made a 65-year-old’s remaining investment horizon genuinely short.

The problem isn’t the logic. It’s that 100, 110, and 120 versions all circulate today, producing wildly different allocations for the same person. A 45-year-old using 100 holds 55% stocks; using 120, they hold 75%. That’s a 20-percentage-point range — hardly a precise answer. What this really means is that the age formula is a first coordinate, not a destination.

Three variables actually determine your bond allocation: time horizon, risk tolerance, and withdrawal proximity. Age is a rough proxy for all three. This article works through the decision logic. For the mechanics of what bonds are and how glide paths work over a full career, see What Are Bonds? and Asset Allocation Basics.

What Bonds Actually Do — The “Buffer,” Not the “Safe Haven”

Bonds are not a risk-free asset that preserves principal. They are a portfolio buffer — a mechanism to reduce peak drawdown during equity selloffs and to provide capital for rebalancing into cheaper stocks. Understanding this distinction is the foundation of any sound allocation decision.

When investors say they hold bonds for safety, they’re only half right. Bonds face four genuine risks.

Interest rate risk: Bond prices move inversely to interest rates. A 10-year bond with a 7-year duration falls roughly 7% in price for every 1 percentage point rise in rates. Longer-duration bonds amplify this.

Credit risk: The issuer — a corporation or government — may fail to pay interest or principal. Broad, diversified exposure to developed-market government bonds minimizes but doesn’t eliminate this.

Inflation risk: A bond yielding 3% in a 4% inflation environment is generating a negative real return. For bonds, this is a slow bleed rather than a sharp drop.

Price risk: “Buy and hold to maturity” eliminates price risk, but most investors sell before maturity. At sale, you receive market price, not face value.

The 2022 experience laid this bare. Major central banks raised rates at the fastest pace in four decades. The result: global equities fell roughly 18–19% (MSCI ACWI basis), and the Bloomberg U.S. Aggregate Bond Index fell approximately 13% — simultaneously. According to Vanguard’s analysis of portfolio history since 1926, the global 60/40 portfolio lost roughly −17.5% in 2022 — its worst calendar year since at least 1937. Bonds and stocks moved in the same direction for the first time in a generation.

Important context: this was an outlier driven by a specific macro event — four decades of declining rates reversing sharply. The historical norm is negative correlation. And in fact, 2023–2025 saw that correlation recover. By 2025, a 60/40 portfolio had returned approximately +15% (varies by index and composition). The lesson isn’t “bonds are broken.” The lesson is that bonds are a portfolio buffer against equity drawdowns, not a guarantee of safety. Their value comes from low average correlation with stocks — a correlation that is itself not fixed.

The practical reason to hold bonds: when equities drop sharply, relatively stable bonds provide a pool of capital to rebalance into cheaper stocks. That’s the mechanism that makes the correlation benefit real.

The Three Variables That Actually Set Your Allocation

Your bond allocation is not determined by age alone. Three variables interact to produce the right number for your situation: how long before you need the money, how much volatility you can genuinely absorb, and how close you are to drawing down the portfolio. The same age can produce a 20% or a 50% bond allocation depending on these inputs.

Variable 1: Time Horizon — “Match the Asset to the Liability”

Money you need within five years should not be heavily invested in equities. Stocks have experienced drawdowns exceeding 50%, and full recoveries from major crashes have taken several years. If you have a near-term goal — a home purchase, a planned career change, a child’s education starting in three years — the risk of a market cycle intersecting with your need date is simply too high.

For money you won’t touch for 10 or more years, the calculus flips. Historical data suggests equities have consistently outperformed bonds over decade-long periods (U.S. data since 1926, past performance does not guarantee future results). With a long enough horizon, short-term volatility becomes noise. The key question is whether your situation actually permits the long horizon — not just whether you intend one.

Variable 2: Risk Tolerance — Willingness and Capacity, Separately

This is where most allocation models oversimplify. Risk tolerance has two distinct components.

Emotional willingness: If your portfolio fell 30% tomorrow, would you sleep? The “sleep test” isn’t a metaphor — it’s a real signal. If a decline of that magnitude would cause you to sell, your equity allocation is already too high, because panic selling at the bottom is the mistake that permanently impairs returns.

Financial capacity: Stable employment, manageable debt, and a six-month emergency fund are what allow you to not sell when markets drop. An investor who needs to liquidate investments because their income dried up doesn’t get to choose their exit price.

The honest challenge: bull markets make investors feel more risk-tolerant than they are. I’ve watched people claim they could handle a 40% drawdown until they actually experienced a 25% one. The calibration happens in real time, and by then rebalancing opportunities have often already passed. Assess both dimensions before the market decides for you.

Variable 3: Withdrawal Proximity — The Sequence Risk Window

The five years immediately before and after retirement are structurally different from every other period. I’ll explain why in the dedicated section below — it’s important enough to have its own space.

Historical Returns by Allocation — What the Numbers Actually Show

The table below draws on long-term U.S. market data since 1926 (Vanguard research). These are historical figures. Past performance does not guarantee future results.

The number that stands out: the average return gap between 60/40 and 100% equity is approximately 1.2 percentage points per year. The maximum drawdown gap is 18.6 percentage points. You are accepting roughly 15× more potential loss for each percentage point of additional return. Whether that trade-off is worth it depends entirely on your time horizon and risk tolerance — not on a formula.

The figures in the table are drawn from Vanguard’s long-term data since 1926; the exact annualized return for the 60/40 portfolio varies by data period and index composition (commonly cited in the 8–9% range). What is consistent across sources: the 60/40 worst calendar year was 2022 at roughly −17.5%, versus −50.9% peak-to-trough for 100% equity in 2008–09.

For investors using broad equity index funds — VOO or VTI for U.S.-listed portfolios, UCITS equivalents like CSPX or VUAA for European investors subject to PRIIPs regulations — the bond side of the equation is typically fulfilled with diversified government bond funds or investment-grade bond index funds. The specific instrument matters less than getting the allocation right.

Allocation by Life Stage — A Brief Reference Point

The detailed mechanics of adjusting allocation across a career — glide path design — are covered in Age-Based Asset Allocation and Glide Paths. Here’s a compact reference based on widely cited lifecycle investing principles (consistent with guidance published by regulators including the U.S. SEC’s investor education resources):

• Early career (20s–30s): ~80% equity, ~20% bonds. Long horizon absorbs volatility.
• Mid-career (40s–50s): Gradual shift toward 60–70% equity, 30–40% bonds.
• Pre-retirement (early 60s): ~60% equity, 40% bonds or more conservative.
• Post-retirement: 30–50% equity, 50–70% bonds and cash for distribution stability.

These are reference points, not rules. The three variables above can push any individual substantially away from these defaults in either direction.

Sequence of Returns Risk — Why the Five Years Before Retirement Are Different

Here’s a scenario worth thinking through. Suppose you’re 62, planning to retire at 65. Your portfolio is $500,000. You decide to maintain a heavy equity allocation because “I’m still three years away.” Then, in year one, the market falls 40%.

Your portfolio is now $300,000. You retire anyway. You begin withdrawing $25,000 per year. Even if the market recovers 50% the next year (which brings it back to its starting level), your portfolio only grows from $275,000 to roughly $412,000. You are permanently behind where you’d be if the loss had come later in retirement, when less of your capital was at risk in equities.

This is sequence risk in practice. The math is asymmetric: a −40% loss requires a +67% gain to recover. When withdrawals are added to the equation, the recovery math deteriorates further.

The practical response is straightforward: begin shifting toward bonds and cash five years before your planned retirement date. The common framework is maintaining roughly five years of living expenses in a separate conservative bucket — short-term bonds and cash equivalents. Even if equities drop sharply, you draw from this bucket rather than selling stocks at depressed prices. The equity portion then has time to recover before you need to touch it.

For a deeper analysis of this risk and how to structure around it, see Sequence of Returns Risk in Retirement.

What a Year-1 Crash Actually Costs You: A Multi-Scenario Look

The existing table shows drawdown and return separately. But the real question is: if a once-in-a-generation crash hits in year one of your investment horizon, how much of your terminal wealth do you lose — and how long does it take to get back to breakeven? These are two numbers the standard frameworks don’t show you side by side.

The table below computes exactly that. Inputs are the historical drawdowns and long-run returns from the Vanguard 1926+ dataset already cited above. The 40/60 long-run return is not precisely confirmed by the Vanguard source used here; 7.5% is used as a conservative illustrative assumption. All other figures are derived from those already in this article.

Assumed inputs (all arithmetic, no new data): maximum historical drawdown as listed in the table above; long-run average annual returns (10.3% / 9.8% / 9.1% / 7.5% illustrative). Scenario: the maximum historical drawdown occurs in year 1, then the portfolio compounds at the long-run average return for 19 more years. This is not a prediction — it is a stress-test scenario to show the asymmetric cost of early losses.

All figures computed from data in this article. 40/60 return (7.5%) is illustrative. Past performance does not guarantee future results.

The standout insight: under a year-1 shock scenario, the 60/40 portfolio ends up with 3.54× versus 100% equity’s 3.16× — a larger terminal multiple despite a lower average return. The shallower drawdown compounds forward more effectively than the higher long-run return can offset. Recovery from a −50.9% crash at 10.3% takes 7.3 years; recovery from a −32.3% crash at 9.1% takes only 4.5 years. Those 2.8 extra years of catching up are years of compounding the market is doing for you — years you don’t get back.

Core Checklist — Five Questions to Find Your Starting Point

Work through these five questions. They won’t give you a precise number, but they’ll narrow the range substantially.

The formula gives you a first coordinate. Your three variables give you the actual path. Waiting for the perfect allocation is itself a decision — and usually a costly one. A reasonable allocation, started today, will nearly always beat a theoretically optimal one that begins six months from now.

Once you’ve set your target allocation, the mechanics of maintaining it belong in a separate discussion. Portfolio Rebalancing covers how to bring actual weights back to target without overtrading.

Frequently Asked Questions

Q. What is the ‘100 minus age’ rule and does it still work?

The rule says you should hold your age as a percentage of bonds — so a 40-year-old holds 40% bonds. Variations using 110 or 120 exist because longer lifespans have made the original formula too conservative for many people. The fact that three versions coexist is itself proof that this is a rough starting point, not a precise prescription. Use it as a first coordinate, then adjust for your actual time horizon, risk tolerance, and proximity to withdrawals.

Q. What is the historical maximum drawdown difference between 100% stocks and a 60/40 portfolio?

Based on long-term U.S. market data since 1926, a 100% equity portfolio experienced a maximum drawdown of approximately −50.9% during the 2007–09 financial crisis, while a 60/40 portfolio drew down approximately −32.3%. The average annual return difference is around 1.2 percentage points, while the maximum drawdown gap is 18.6 percentage points. These are historical figures and do not guarantee future results.

Q. Can bonds lose money?

Yes. Bonds carry four distinct risks: interest rate risk (prices fall when rates rise), credit risk (issuer default), inflation risk (real returns erode when inflation exceeds yield), and price risk (selling before maturity locks in market price, not face value). In 2022, major central banks’ rapid rate increases caused both stocks and bonds to fall simultaneously, driving the global 60/40 portfolio to roughly −17.5% for the year.

Q. Who can reasonably hold a low bond allocation?

Someone with a time horizon of 20+ years, stable income, manageable debt, an adequate emergency fund, and the genuine emotional capacity to hold through a −30% or deeper decline. The catch: most investors overestimate their risk tolerance during a bull market. The real test comes when the decline is already happening, not while you’re planning.

Q. Is it too late to raise bond allocation right before retirement?

Potentially, yes. The five years immediately before and after retirement concentrate sequence-of-returns risk more than any other period. A major loss in this window, combined with ongoing withdrawals, leaves your portfolio with a permanently smaller base to recover from. The time to shift toward bonds is five years before you need the money, not five months.

← Back to all posts