What Is Rebalancing and Why Does It Matter?
Quick answer: Rebalancing is periodically adjusting your portfolio back to its target asset allocation after market movements cause it to drift. Over time, different investments grow at different rates — so if stocks surge, they become a bigger share of your portfolio than you intended, quietly increasing your risk. Rebalancing means trimming what's grown beyond its target and adding to what's lagged, bringing the portfolio back to your intended mix. It matters for two main reasons: it keeps your risk level in check (preventing your portfolio from drifting to a riskier or more conservative allocation than you want), and it enforces a disciplined "buy low, sell high" approach that counters emotion. Rebalancing can be done on a schedule (calendar-based) or when the allocation drifts past set thresholds. In retirement, withdrawals themselves can be used to rebalance, and it should be done tax-efficiently. For Columbus, Ohio retirees, disciplined, tax-aware rebalancing keeps your portfolio aligned with your plan. This article is educational and is not personalized investment advice.
Key Takeaways
- Rebalancing is periodically adjusting your portfolio back to its target allocation after it drifts.
- Over time, different investments grow at different rates, causing your allocation (and risk) to drift.
- Rebalancing matters for two reasons: it keeps your risk level in check and enforces disciplined buy-low/sell-high.
- Without it, a portfolio can quietly drift to a riskier allocation than you intend, especially after a strong stock run.
- It can be done on a schedule (calendar) or when the allocation drifts past set thresholds.
- In retirement, withdrawals and contributions can be used to rebalance efficiently.
- Rebalancing should be done tax-efficiently — using tax-advantaged accounts and mindful of tax consequences.
Table of Contents
- The Drift Problem
- What Rebalancing Actually Is
- Reason 1: Keeping Your Risk in Check
- Reason 2: Enforcing Discipline
- How Rebalancing Is Done: The Methods
- Rebalancing in Retirement: Using Withdrawals
- Doing It Tax-Efficiently
- The Discipline It Requires
- How Often Should You Rebalance?
- Frequently Asked Questions
The Drift Problem
To understand why rebalancing matters, you first have to understand the problem it solves: portfolio drift. Left alone, your carefully-set allocation doesn't stay put — it drifts over time, and that drift quietly changes your risk.
How drift happens:
You set a target allocation — say, a certain mix of stocks and bonds appropriate to your risk level. But different investments grow at different rates. When stocks outperform bonds (as they often do over time), the stock portion of your portfolio grows faster, becoming a larger share than you intended. When stocks fall, the reverse happens. Either way, your actual allocation drifts away from your target.
Why drift is a problem:
- It changes your risk level — if stocks grow to a bigger share than intended, your portfolio becomes riskier than you designed it to be, often without you noticing
- It happens gradually and silently — you don't get an alert; the drift accumulates quietly over months and years
- It's often worst at the worst time — after a long bull market, drift leaves you most stock-heavy (riskiest) right when a downturn may be coming; after a crash, it leaves you most conservative right before a potential recovery
A concrete illustration:
Imagine you set a balanced allocation, then stocks have a great multi-year run. Without rebalancing, your portfolio could drift to a much more aggressive mix than you intended — you're now taking substantially more risk than you signed up for, and you're most exposed just as the market may be due for a correction. The drift turned your balanced portfolio into an aggressive one, silently.
The counterintuitive danger:
Drift feels good on the way up — your stock-heavy portfolio is doing great in a rising market. But that's exactly when it's quietly becoming riskier than intended, setting you up for a bigger fall. The good feeling masks the growing risk.
For Columbus-area retirees, understanding the drift problem is the key to understanding rebalancing: your allocation won't stay where you set it, and left unchecked, drift changes your risk in ways you didn't intend. Rebalancing is the fix.
What Rebalancing Actually Is
With the drift problem in mind, rebalancing is simple to understand: it's bringing your portfolio back to its target allocation.
The basic mechanic:
Rebalancing means periodically adjusting your holdings back to your target allocation — trimming the asset classes that have grown beyond their target, and adding to the ones that have fallen below it. If stocks have drifted up to a bigger share than intended, you trim some stocks and add to bonds; if stocks have fallen below target, you add to stocks and trim bonds. The result: your portfolio returns to your intended mix.
A simple example of the concept:
Suppose your target is a specific stock/bond mix, and after a strong stock run, stocks have grown to a larger share than your target. Rebalancing brings it back: you sell enough stocks (and buy enough bonds) to restore the target mix. Your portfolio is back to the risk level you intended.
What it accomplishes:
Rebalancing accomplishes two things at once (the two reasons covered in the next sections):
- It restores your intended risk level (undoing the drift)
- It enforces a disciplined "sell high, buy low" action (trimming what's up, adding to what's down)
What it's not:
Rebalancing isn't market timing or trying to predict anything. It's a systematic, rules-based process of maintaining your target allocation regardless of predictions. You're not guessing where markets are headed — you're simply keeping your portfolio aligned with your plan. This distinction matters: rebalancing is discipline, not forecasting.
A maintenance activity:
Think of rebalancing as portfolio maintenance — like periodically realigning something to keep it running as designed. It's not a dramatic move or a bet; it's routine upkeep that keeps your portfolio doing what it's supposed to do.
For Columbus-area retirees, rebalancing is simply the disciplined maintenance that keeps your portfolio aligned with your intended allocation — trimming what's grown, adding to what's lagged, to restore your target mix.
Reason 1: Keeping Your Risk in Check
The first and most important reason to rebalance is risk management: rebalancing keeps your portfolio's risk level where you intended it to be.
The core purpose:
You set your allocation to match your risk level — how much risk you can afford, handle, and need (from my companion piece on investment risk). But drift changes that allocation, and therefore your risk. Rebalancing restores your intended allocation, keeping your risk in check.
Why this is so important in retirement:
- Your allocation reflects careful decisions about how much risk is right for you
- Drift can push you to a riskier allocation than you can afford or handle
- In retirement, taking more risk than intended — right before a downturn — can be genuinely damaging
- Keeping your risk aligned with your plan protects you from unintended exposure
The "riskier than you think" trap:
Many investors who don't rebalance are taking more risk than they realize. After a long bull market, an un-rebalanced portfolio can be far more stock-heavy — and far riskier — than the owner intends or realizes. They feel fine because the market's been good, but they're exposed to a bigger loss than they signed up for. Rebalancing prevents this by keeping the risk where it belongs.
Both directions:
Rebalancing keeps risk in check in both directions. It prevents your portfolio from becoming too aggressive (after stocks run up) and too conservative (after stocks fall and you don't add back). Either drift moves you away from your intended risk level; rebalancing corrects both.
The connection to your risk decision:
Rebalancing is what makes your risk decision stick. You can set the perfect allocation for your situation, but without rebalancing, it won't stay that way. Rebalancing is the ongoing discipline that maintains the risk level you carefully chose.
For Columbus-area retirees, keeping your risk in check is the primary reason to rebalance — it ensures the careful risk decision you made actually holds over time, protecting you from unintended, drift-driven risk.
Reason 2: Enforcing Discipline
The second reason rebalancing matters is that it enforces a disciplined "buy low, sell high" approach — the opposite of the emotional mistakes that hurt investors.
The built-in discipline:
By its nature, rebalancing has you trim what's grown (sell high) and add to what's fallen (buy low). This is exactly the disciplined behavior good investing requires — and exactly the opposite of the emotional tendency to chase winners and flee losers. Rebalancing builds this discipline into a systematic process, so you do the right thing automatically.
Countering the behavior gap:
In my companion piece on behavioral mistakes, I covered how investors tend to buy high (chasing) and sell low (panicking) — the "behavior gap" that drags down returns. Rebalancing is a direct counter: it systematically has you sell high and buy low, the opposite of the emotional pattern. It's discipline made mechanical.
Why the discipline is hard (and valuable):
Rebalancing requires doing the psychologically hard thing:
- Selling some of what's done well — when stocks have soared, rebalancing has you trim them, which feels like leaving the party early
- Buying some of what's done poorly — when an asset has fallen, rebalancing has you add to it, which feels like buying a loser
Both actions run against emotion. That's precisely why having a systematic rebalancing process is valuable — it makes you do the disciplined thing even when it feels uncomfortable.
The potential return benefit:
Beyond risk management, this disciplined buy-low/sell-high behavior can, over time, modestly enhance returns in some market environments (a "rebalancing bonus"), though the primary benefit is risk control, not return enhancement. The main point is that rebalancing enforces good behavior; any return benefit is secondary.
Removing emotion from the decision:
Because rebalancing is rules-based (do it on a schedule or at thresholds), it removes emotion and judgment from the moment. You're not deciding whether to sell stocks after a great run based on how you feel — you're following your rebalancing rule. This systematic approach protects you from the emotional mistakes.
For Columbus-area retirees, the discipline that rebalancing enforces — systematically selling high and buying low, countering the emotional mistakes — is a genuine and valuable benefit beyond just keeping your risk in check.
How Rebalancing Is Done: The Methods
There are a few common methods for deciding when and how to rebalance. Understanding them helps you (and your advisor) choose an approach.
Method 1: Calendar-based rebalancing.
Rebalancing on a set schedule — for example, once or twice a year, or quarterly. At each scheduled time, you check your allocation and rebalance back to target if it's drifted. The advantage is simplicity and discipline (it happens on schedule regardless of emotion); the potential drawback is that it may rebalance when little drift has occurred, or miss significant drift between dates.
Method 2: Threshold-based rebalancing.
Rebalancing when your allocation drifts beyond set thresholds — for example, when an asset class moves more than a certain amount from its target. You monitor the allocation and rebalance only when the drift crosses the threshold. The advantage is that you rebalance when it's actually needed (based on drift, not the calendar); the potential drawback is that it requires monitoring.
Method 3: A combination.
Many approaches combine the two — checking on a schedule (say, periodically) but only rebalancing if the drift exceeds a threshold. This blends the discipline of a schedule with the responsiveness of thresholds, and it's a common practical approach.
Method 4: Rebalancing with cash flows.
In practice, rebalancing can often be done using the money moving in or out of the portfolio:
- Contributions (if still adding) can be directed to the underweight asset classes
- Withdrawals (in retirement) can be taken from the overweight asset classes
- Dividends and interest can be directed to rebalance
This "cash flow rebalancing" is efficient because it rebalances without necessarily selling — using the money that's moving anyway. It's especially relevant in retirement (covered next).
Which method is best?
There's no single best method — each has merits, and the right approach depends on your situation, your accounts, and tax considerations. What matters most is having a systematic approach and following it consistently, rather than the specific method. Consistency and discipline matter more than the exact rule.
For Columbus-area retirees, choosing a rebalancing method — calendar, threshold, a combination, or using cash flows — is less important than committing to a systematic approach and following it. My role often includes handling this systematically as part of ongoing portfolio management.
Rebalancing in Retirement: Using Withdrawals
Rebalancing takes on a particularly useful dimension in retirement, because your withdrawals can do the rebalancing for you.
Withdrawals as a rebalancing tool:
In retirement, you're regularly withdrawing money from your portfolio for income. By choosing which assets to sell for those withdrawals, you can rebalance at the same time:
- If stocks are overweight (have grown beyond target), take your withdrawals from stocks — this funds your income AND trims the overweight stocks, rebalancing toward target
- If stocks are underweight (have fallen below target), take withdrawals from bonds or cash instead — funding income while leaving stocks alone to recover
Why this is efficient:
Using withdrawals to rebalance is efficient because you're selling something anyway to fund your income — so you might as well sell what's overweight, accomplishing your withdrawal and your rebalancing in one move. It avoids extra transactions and coordinates two needs (income and rebalancing) into one action.
The downturn advantage:
This connects to the buffer concept from my companion piece on bonds and cash. In a downturn, when stocks are down (underweight), you take withdrawals from bonds and cash instead of selling stocks low — which both funds your income from the buffer AND avoids selling stocks at depressed prices. When stocks recover and become overweight again, you take withdrawals from stocks, trimming them back. Your withdrawal strategy and rebalancing work together beautifully.
A coordinated withdrawal-and-rebalancing strategy:
The best retirement approach coordinates withdrawals and rebalancing:
- Draw income from overweight assets (rebalancing as you go)
- In downturns, draw from the buffer (bonds/cash) to avoid selling stocks low
- In good times, draw from and trim the appreciated stocks
- Keep the portfolio aligned with target throughout
Why this matters:
This coordinated approach means your regular income withdrawals do double duty — funding your life and keeping your portfolio balanced — while also protecting you from selling stocks at the wrong time. It's an elegant, efficient way to manage a retirement portfolio.
For Columbus-area retirees, using your withdrawals to rebalance — drawing income from overweight assets, and from the buffer during downturns — is an efficient, coordinated strategy that keeps your portfolio balanced while funding your retirement.
Doing It Tax-Efficiently
In retirement, rebalancing needs to be done with an eye toward taxes, because selling investments (especially in taxable accounts) can trigger tax consequences. Tax-efficient rebalancing keeps more money working for you.
Why taxes matter for rebalancing:
Rebalancing involves selling some investments (the overweight ones), and in a taxable account, selling appreciated investments realizes capital gains, which are taxable. So rebalancing in taxable accounts can create a tax cost. Being thoughtful about this keeps the tax impact down.
Tax-efficient rebalancing techniques:
- Rebalance within tax-advantaged accounts first — selling and buying inside IRAs and 401(k)s doesn't trigger current taxes, so rebalancing there is tax-free. Doing as much rebalancing as possible within tax-advantaged accounts minimizes the tax cost.
- Use cash flows to rebalance — directing contributions, withdrawals, dividends, and interest to rebalance means less need to sell (and thus less taxable gain)
- Use withdrawals to rebalance — as covered, taking retirement withdrawals from overweight assets rebalances without extra transactions
- Harvest losses when rebalancing — pairing rebalancing with tax-loss harvesting (selling losers to offset the gains from selling winners) can reduce the tax cost
- Be mindful of the tax cost vs. the drift — sometimes tolerating a small amount of drift is better than triggering a tax cost to correct it; the benefit of rebalancing should be weighed against the tax cost in taxable accounts
The coordination with asset location:
Tax-efficient rebalancing connects to asset location (from my companion piece): because rebalancing within tax-advantaged accounts is tax-free, having your rebalancing "levers" in those accounts helps. Coordinating rebalancing with your account structure and tax situation is part of doing it well.
The balance to strike:
The goal is to keep your portfolio appropriately balanced while minimizing the tax cost of doing so. This usually means rebalancing primarily within tax-advantaged accounts, using cash flows, and being thoughtful about taxable-account sales — striking a balance between staying on-target and managing taxes.
Where coordination helps:
Tax-efficient rebalancing is another area where coordinating investment management with tax planning pays off, and where working with an advisor (and your tax professional) helps ensure it's done well.
For Columbus-area retirees, doing rebalancing tax-efficiently — primarily within tax-advantaged accounts, using cash flows and withdrawals, and being mindful of the tax cost in taxable accounts — keeps more of your money working for you while maintaining your target allocation.
The Discipline It Requires
Rebalancing sounds simple, but doing it consistently requires discipline — because it asks you to act against your emotions, especially at the moments when it matters most.
The emotional challenge:
As noted, rebalancing requires selling some of what's done well and buying some of what's done poorly. This is emotionally hard:
- In a bull market, rebalancing has you trim your soaring stocks — it feels like a mistake to sell winners
- In a downturn, rebalancing has you buy more stocks as they fall — it feels frightening to buy into a falling market
Both actions run directly against how you feel in the moment. That's why rebalancing, though simple in concept, is hard in practice.
Why the hardest rebalancing is the most valuable:
The rebalancing that's hardest to do emotionally is often the most valuable. Buying stocks during a downturn (when rebalancing calls for it) means buying low — exactly what disciplined investing requires, and exactly what fear resists. Trimming stocks after a big run means selling high and reducing risk before a potential fall. The discipline to rebalance when it feels wrong is where much of its value lies.
How systematic rebalancing helps:
This is why a systematic, rules-based approach to rebalancing is so valuable — it takes the emotion out of the decision. If your rule says to rebalance on a schedule or at a threshold, you follow the rule regardless of how you feel. The system enforces the discipline that emotion would otherwise undermine.
The role of an advisor:
Rebalancing is another area where an advisor adds value — both by handling it systematically and by providing the discipline and perspective to rebalance when it feels emotionally difficult. Having someone help you buy during a downturn (when rebalancing calls for it) or trim during a boom is part of the behavioral support a good advisor provides.
Consistency over perfection:
The key to rebalancing isn't doing it perfectly — it's doing it consistently. A reasonable, systematic approach followed consistently beats a perfect approach applied erratically. Consistency and discipline are what make rebalancing work over time.
For Columbus-area retirees, recognizing that rebalancing requires discipline — and using a systematic approach (and an advisor's support) to enforce it — is what makes it effective, especially at the emotionally difficult moments when it matters most.
How Often Should You Rebalance?
A common question is how frequently to rebalance. The answer, as with much in investing, is that it depends — but there are sensible guidelines.
There's no single right frequency:
Research suggests that rebalancing frequency isn't hugely critical — a range of reasonable approaches (from annually to threshold-based) all work reasonably well. What matters most is having a consistent approach, not the exact frequency. You don't need to rebalance constantly, and rebalancing too often can create unnecessary transactions and tax costs.
Common reasonable approaches:
- Periodically on a schedule — checking and rebalancing on a regular schedule (many use an annual or semi-annual check)
- At thresholds — rebalancing when the allocation drifts beyond set amounts
- A combination — checking periodically but only rebalancing if drift exceeds a threshold
- Using cash flows — rebalancing gradually through contributions and withdrawals, supplemented by periodic checks
The case against over-rebalancing:
Rebalancing too frequently can be counterproductive — it can increase transaction costs and taxes without meaningfully improving risk control. There's a balance: rebalance often enough to control drift, but not so often that you incur unnecessary costs. For most people, a periodic (like annual) check, combined with threshold awareness, strikes a good balance.
The case against never rebalancing:
The bigger risk for most people isn't rebalancing too often — it's not rebalancing at all, letting drift accumulate for years. A portfolio that's never rebalanced can drift far from its target, taking on far more (or less) risk than intended. Some regular rebalancing is much better than none.
In retirement specifically:
In retirement, the regular withdrawals provide natural rebalancing opportunities, so much of the rebalancing can happen through the withdrawal process, supplemented by periodic checks. This makes retirement a natural time for cash-flow-based rebalancing.
For Columbus-area retirees, the practical answer on frequency is: have a consistent approach (periodic checks and/or thresholds, using withdrawals to rebalance), rebalance often enough to control drift but not so often as to incur unnecessary costs, and — most importantly — actually do it consistently rather than letting drift accumulate.
Frequently Asked Questions
What is rebalancing?
Rebalancing is periodically adjusting your portfolio back to its target asset allocation after market movements cause it to drift. Since different investments grow at different rates, your allocation drifts over time; rebalancing trims what's grown beyond its target and adds to what's lagged, restoring your intended mix and risk level.
Why does rebalancing matter?
For two main reasons: it keeps your risk level in check (preventing your portfolio from drifting to a riskier or more conservative allocation than you intend), and it enforces a disciplined "buy low, sell high" approach that counters the emotional mistakes investors make. The first — risk control — is the primary benefit.
What is portfolio drift?
Portfolio drift is when your actual allocation moves away from your target because different investments grow at different rates. For example, after a strong stock run, stocks become a bigger share of your portfolio than intended, making it riskier than you designed — often silently. Rebalancing corrects this drift.
How often should I rebalance?
There's no single right frequency. Reasonable approaches include periodic checks (like annually or semi-annually), rebalancing at set drift thresholds, or a combination, often supplemented by using cash flows. What matters most is having a consistent approach and following it — rebalancing often enough to control drift but not so often as to incur unnecessary costs. Not rebalancing at all is the bigger risk.
How do I rebalance in retirement?
In retirement, you can use your withdrawals to rebalance: take income from overweight assets (trimming them back to target) and, during downturns, from your bond and cash buffer (avoiding selling stocks low). This coordinates your income withdrawals with rebalancing, so your regular withdrawals do double duty — funding your life and keeping your portfolio balanced.
Does rebalancing improve returns?
Its primary benefit is risk control, not return enhancement. The disciplined buy-low/sell-high behavior can modestly enhance returns in some market environments (sometimes called a "rebalancing bonus"), but you shouldn't rebalance mainly for returns. The main reason is to keep your risk level in check and enforce discipline.
How do I rebalance without triggering taxes?
Rebalance primarily within tax-advantaged accounts (IRAs, 401(k)s), where selling doesn't trigger current taxes; use cash flows (contributions, withdrawals, dividends) to rebalance without selling; pair rebalancing with tax-loss harvesting; and be mindful of the tax cost of selling appreciated investments in taxable accounts. Sometimes tolerating small drift beats triggering a tax cost to correct it.
Is rebalancing the same as market timing?
No. Market timing is trying to predict market moves to get in and out. Rebalancing is a systematic, rules-based process of maintaining your target allocation regardless of predictions. You're not guessing where markets are headed — you're keeping your portfolio aligned with your plan. Rebalancing is discipline; market timing is (failed) forecasting.
Why is rebalancing emotionally hard?
Because it requires selling some of what's done well (trimming soaring stocks feels like leaving the party early) and buying some of what's done poorly (adding to falling assets feels frightening). Both run against emotion. That's exactly why a systematic approach — and often an advisor's support — is valuable: it enforces the discipline when your feelings resist it.
What happens if I never rebalance?
Your allocation drifts, usually toward becoming stock-heavy (riskier) after a bull market, so you end up taking more risk than you intended — often right before a downturn. An un-rebalanced portfolio can drift far from its target over years. Not rebalancing is a bigger risk for most people than rebalancing imperfectly.
Keep Your Portfolio Aligned With Your Plan
For Columbus-area retirees, rebalancing is the disciplined maintenance that keeps your portfolio aligned with your plan. Left alone, your allocation drifts — usually becoming riskier than you intended after a strong market run, and often silently. Rebalancing corrects that drift, keeping your risk level in check and enforcing the disciplined "buy low, sell high" behavior that counters emotion.
The pattern that produces better outcomes: understand that your allocation drifts and needs correcting, rebalance systematically (calendar, threshold, or a combination), use your withdrawals to rebalance in retirement (drawing from overweight assets, and from your buffer in downturns), do it tax-efficiently (primarily within tax-advantaged accounts, using cash flows), and — most importantly — do it consistently, following your rules even when it feels emotionally difficult.
The goal isn't to rebalance perfectly or constantly — it's to keep your portfolio aligned with the risk level and plan you carefully chose, through the discipline of regular, tax-aware rebalancing. It's routine maintenance that keeps your strategy working as designed.
This is part of my seven-part series on investing during retirement for Ohio retirees. The companion pieces cover the big-picture overview, how much risk to take, the role of bonds and cash, asset allocation vs. location, managing concentrated stock, avoiding behavioral mistakes, and investment costs — all coming soon in this series.
At Blue Advisors, I handle rebalancing systematically for Columbus-area retirees — keeping portfolios aligned with their target allocation, coordinating it with withdrawals and tax efficiency, and providing the discipline to rebalance even when it feels difficult. Blue Advisors is a fee-only fiduciary registered investment advisory firm based in Columbus, Ohio, and disciplined rebalancing is part of the ongoing portfolio management I provide.
Schedule a conversation: If you're a Columbus-area retiree who wants your portfolio kept disciplined and aligned with your plan, you can book an introductory call here: calendly.com/jimblue/blue-advisors-meeting.
By James Blue, Fee-Only Advisor | Blue Advisors
James Blue is the founder of Blue Advisors, a fee-only registered investment advisory firm based in Columbus, Ohio, serving retirees, pre-retirees, and busy professionals across Central Ohio and nationally.
This content is provided for informational and educational purposes only and should not be construed as personalized investment, tax, or legal advice. All investing involves risk, including the possible loss of principal; past performance is not indicative of future results, and rebalancing does not guarantee a profit, protect against loss, or ensure any particular outcome. Rebalancing may have tax consequences, particularly in taxable accounts, and the tax treatment depends on your individual circumstances; the "rebalancing bonus" and any return benefits are not guaranteed and vary by market environment. The methods and concepts discussed are general and educational and are not recommendations to adopt any particular strategy. Blue Advisors is a fee-only registered investment advisory firm and is not a tax preparation firm. Readers should consult a qualified financial advisor and, for tax matters, a qualified tax professional regarding their specific situation. The views expressed are those of the author as of the date published and are subject to change without notice. Advisory services are offered only pursuant to a written advisory agreement and to clients in the State of Ohio, the Commonwealth of Pennsylvania, and other jurisdictions where Blue Advisors is properly registered or exempt from registration.