Asset Allocation by Age and How to Rebalance
Asset Allocation by Age and How to Rebalance
How much of your money should sit in stocks versus bonds? It is one of the most common questions in personal finance, and the honest answer is that it depends on your age, your goals, and your stomach for risk. But there are well-worn rules of thumb that give you a starting point.
This article walks through the classic age-based allocation rules, why allocation matters more than picking individual winners, and how to rebalance without turning it into a stressful chore. None of this is financial advice. Treat it as a framework to think with, not a prescription.
Why Asset Allocation Matters More Than Stock Picking
Decades of research point to the same conclusion: how you split your money across asset classes (stocks, bonds, cash, real estate) explains far more of your long-term results than which specific securities you buy. The Bogleheads investment philosophy summarizes it well, treating allocation as the central decision and individual selection as secondary.
The intuition is simple. Stocks offer higher expected returns but swing wildly. Bonds offer lower returns but cushion the ride. Your mix of the two sets both your growth potential and how much volatility you will have to endure to get it.
The "120 Minus Age" Rule
The best-known shortcut is to subtract your age from a fixed number to get your stock percentage. The classic version used 100. As lifespans grew, many advisors shifted to 110 or 120.
The idea: the younger you are, the more time you have to ride out market drops, so you can hold more stocks. As you age and your time horizon shrinks, you shift toward bonds to protect what you have built.
| Age | 120 minus age (stocks) | Implied bonds | Rough risk posture |
|---|---|---|---|
| 25 | 95% | 5% | Aggressive growth |
| 35 | 85% | 15% | Growth |
| 45 | 75% | 25% | Balanced growth |
| 55 | 65% | 35% | Balanced |
| 65 | 55% | 45% | Conservative |
| 75 | 45% | 55% | Capital preservation |
These are starting points, not commandments. A 35-year-old with an unstable income might sensibly hold more bonds, while a 60-year-old with a fat pension might hold more stocks. The rule encodes one variable (age) when real decisions involve several.
Glide Paths: How Target-Date Funds Do It
The "minus age" rule is a manual version of what target-date funds automate. A glide path is a pre-planned schedule that gradually reduces stock exposure as a target retirement year approaches.
Vanguard, one of the largest managers of these funds, publishes research on how its glide paths are constructed, balancing growth early on with risk reduction near and into retirement. Their principles for investing success lay out the reasoning. The key insight is that the shift should be gradual and rules-based, not a panicked lurch when markets fall.
A glide path also keeps moving after retirement, not just up to it, because someone retiring at 65 may need their portfolio to last 30 more years. That longevity is partly why "120 minus age" replaced "100 minus age."
Why You Need to See Your Whole Portfolio First
None of these rules help if you cannot see your current allocation. Most people hold investments across several accounts: a workplace plan, a brokerage, maybe crypto and some cash. Your stock-to-bond ratio is the blend of all of them, not any single account.
This is the case we make in why seeing your full portfolio matters. You cannot rebalance toward a target you cannot measure. Step one is always a complete, current view of where every dollar sits.
A related trap is hidden duplication. Two funds in different accounts can hold the same underlying companies, quietly concentrating your risk. Learning how to spot ETF overlap helps you avoid thinking you are diversified when you are not.
How to Rebalance Without Stress
Rebalancing means nudging your portfolio back to its target mix after markets push it out of line. If stocks surge, you might drift from 80% to 88% stocks, taking on more risk than you intended. Rebalancing trims the winners and tops up the laggards.
There are two common, low-stress approaches:
- Calendar rebalancing. Check once or twice a year on a fixed date. Simple and unemotional.
- Threshold rebalancing. Act only when an asset class drifts more than a set band (say 5 percentage points) from its target. Less frequent, more responsive.
You do not need both. Pick one and let it run.
A Simple Rebalancing Routine
- Record current values for every holding.
- Calculate your actual stock/bond/other percentages.
- Compare against your target for your age and situation.
- If anything is outside your comfort band, adjust, ideally with new contributions rather than selling, to keep taxes and fees down.
- Write down your target so future-you does not improvise.
The biggest enemy of good rebalancing is emotion. The whole point is to buy what is cheap and trim what is expensive, which feels backwards in the moment. A rules-based schedule removes the agonizing.
The Honest Caveat
Age-based rules are deliberately crude. They ignore your other income, your debts, your job security, your goals, and your actual tolerance for watching a balance fall. The SEC's investor education site has a balanced primer on assessing your risk tolerance that is worth reading before you anchor on any single number.
Use the rules as a conversation starter with yourself, not as advice. If your finances are complex, a fee-only fiduciary can help you personalize.
Tracking Your Allocation in MyMoneyViz
To rebalance, you first need to see your mix, and to see your mix you need everything in one place. MyMoneyViz tracks 13+ asset types and shows allocation breakdowns across your whole portfolio, so your real stock-to-bond ratio is visible at a glance rather than buried across accounts.
You can set a target allocation as a goal and watch your actual mix against it over time. With backfilled history, you can even see how your allocation drifted through past market moves, which makes the case for disciplined rebalancing concrete rather than theoretical.
The Bottom Line
Asset allocation by age gives you a sane default: more stocks when young, gradually more bonds as retirement nears, adjusted in steady steps rather than panicked jumps. Rebalancing keeps that plan intact when markets try to pull you off course.
But every rule assumes you can see what you actually own. Start by getting your full portfolio in view with MyMoneyViz, set your target, and rebalance on a schedule instead of on emotion.
