How to Rebalance Your Portfolio (And When)

1. Rebalancing is maintenance, not a money-maker

Quick Answer: Rebalancing does not make you richer. In Vanguard’s ten-year simulations, the best and worst rebalancing rules for a 60/40 portfolio finished 18 basis points a year apart: about $18 on $10,000. What separates them is risk: one rule let the mix drift 10 percentage points off target, the other held it under 2.

Most articles sell rebalancing as a clever way to buy low and sell high. The numbers do not support that. It is closer to changing the oil in a car: it does not make the car faster, it stops the engine wearing out.

That reframe changes what you optimize for. Stop chasing perfect timing. Pick a rule that holds your risk steady, then make it cheap and tax-efficient to follow.

This guide shows how fast a portfolio drifts and what each trigger rule costs. It also shows what a mix becomes if you never rebalance a portfolio at all, and what the tax bill looks like in a regular brokerage account. Every figure traces to a named public source, the same standard behind every investing guide we publish at DollarVisor. No company pays for placement here.

If you want the mechanics explained out loud before the numbers start, this walkthrough covers the ground well.

2. What does it mean to rebalance a portfolio?

Quick Answer: To rebalance a portfolio is to move money back to your written target mix after markets have pushed it off. If your 60% stock target has grown to 68%, you sell 8 points of stock and buy bonds with it. The SEC calls this returning your portfolio to a comfortable level of risk.

Three things have to be true before rebalancing means anything at all:

• You have a written target. A number like 70/30, decided in advance. Without it you are guessing based on how the last month felt.
• You have a trigger. Either a calendar date or a drift limit. Most people skip this, which is why portfolios sit untouched for a decade.
• You are willing to sell your winner. Rebalancing always means trimming whatever just did best. That feels wrong, and it is why the habit fails.

That last point deserves more attention than it gets. The mechanics of how to rebalance your portfolio take about ten minutes. Selling the thing that has been working is what actually stops people.

The SEC’s beginners’ guide treats rebalancing as one of three habits alongside choosing a mix and spreading money inside it. Its baseline advice is to review the portfolio every six to 12 months. That review only works if you already decided what your stock and bond split should be.

3. How fast does a portfolio drift off target?

Quick Answer: Faster than most people expect during a crash. Vanguard modeled a 60/40 portfolio through March 2020. A quarterly schedule let the mix run 10 percentage points off target. A monthly schedule let it run 7. A daily drift check kept it inside 2 the whole way through.

Read the dollar column carefully. A 10-point drift on a $300,000 balance means $30,000 more was riding on stocks than you signed up for, right as stocks were falling hardest.

Drift runs the other way too. After a crash the stock share sits below target, so an unfixed portfolio stays underweight through the recovery. That is the part people forget, and it is why an automated option like a target-date fund quietly beats good intentions for many savers.

4. Calendar or drift bands: which trigger is better?

Quick Answer: Drift bands win on both cost and risk control, but the margin is small. Over ten simulated years, Vanguard’s band-based rule returned 7.19% a year against 7.01% for monthly and 7.08% for quarterly. It also held the mix tighter to target. Bands trade more often but in much smaller amounts.

The counterintuitive row is trade size. Quarterly rebalancing traded least often but paid the most per trade, because three months of drift makes for a big correction.

The whole spread between the best and worst rule was 18 basis points a year. Frequency is a rounding error. Discipline is not.

You are not running a fund, so daily monitoring is not the point. The transferable lesson is that a drift limit beats a fixed date, because it acts when the portfolio needs it rather than when the calendar says so.

5. What a 60/40 turns into if you never touch it

Quick Answer: It becomes an aggressive portfolio without you deciding to make one. At the long-run average returns Vanguard published for 1926 to 2019, a 60/40 left alone drifts to roughly 70% stocks in ten years and 79% in twenty. Nobody chose that mix. Time chose it.

Markets do not deliver smooth average returns, so read the path as a direction, not a prediction. Stocks compound faster, so the stock share only rises between rebalances.

By year 20 the mix sits near 80/20. In the same Vanguard dataset, the worst calendar year for 80/20 was a 34.9% loss, against 26.6% for the 60/40 the saver picked. That is roughly $45,000 of extra downside on a $538,000 balance, arriving at the age when most people want less risk. If you are near your retirement number, that gap is the argument to rebalance a portfolio on a rule.

6. What rebalancing costs in a taxable account

Quick Answer: Inside a 401(k) or IRA, rebalancing is free of tax. In a regular brokerage account, selling long-held winners realizes a gain. On $15,000 of long-term gain, a single filer in 2026 owes nothing, $2,250, or as much as $3,570, depending entirely on income.

Two rules fall out of this table. Rebalance inside retirement accounts whenever you can, because the same trade there costs nothing. And if your whole portfolio sits in a taxable account, the drift band earns its keep by cutting the number of taxable events.

State tax sits on top of these federal numbers. Losses elsewhere can offset the gain, which is where harvesting losses pairs naturally with a rebalance. Our breakdown of short-term versus long-term capital gains rates covers the holding-period trap: gains on shares held under a year are taxed at ordinary income rates instead.

7. How to rebalance your portfolio in six steps

Quick Answer: List every account together, work out your current percentages, compare them to your written target, and see which holdings are more than 5 points off. Fix the biggest gaps first, inside retirement accounts where you can, then note the date you last rebalanced your portfolio.

Set aside half an hour. The job is arithmetic, and the second time takes ten minutes.

1. Put every account on one page. Most guides start inside a single account. Start at household level instead: the 401(k), the IRA, the brokerage account, the old plan you never rolled over. Rebalancing one account in isolation is how people end up holding two contradictory portfolios.
2. Work out today’s percentages. Divide each asset class by the combined total. Most brokerages show this on an allocation tab, but check it, because plans often mislabel balanced funds.
3. Compare each line to your target. Write the gap in percentage points beside each one. This is the only number that decides whether you trade.
4. Apply a 5-point band. Anything more than 5 points off target gets fixed. For a smaller sleeve, say a 10% slice, use a quarter of its target instead, so it triggers at 12.5% or 7.5%.
5. Trade in the sheltered accounts first. Sell what is overweight and buy what is underweight inside the 401(k) or your IRA, where no tax follows. Only touch the taxable account if the gap remains.
6. Write down the date and the new mix. One line in a note. That record is what stops you renegotiating your target in the middle of a bad month.

Step four is where the money is. A 5-point band on a 60% target means you act at 65% or 55% and ignore everything in between. Most drift you will ever see falls inside that range and needs nothing from you.

8. How to rebalance without selling anything

Quick Answer: Point new money at whatever is underweight instead of selling what is overweight. This works while your yearly contributions are large next to your balance. Once contributions fall below roughly 5% of the portfolio, they can no longer close a 5-point gap on their own.

Most guides list cash-flow rebalancing as a clever trick and stop there. The useful question is when it stops working, and that has an answer you can check in a minute.

A 5-point gap on a $60,000 balance is $3,000. Redirect $700 a month and it closes in about four months. The same gap on a $600,000 balance is $30,000, which those contributions would take three and a half years to fill: by which time the market has moved again.

• Redirect new contributions. Send this year’s payroll deferrals entirely to the underweight side until the gap closes.
• Switch off automatic reinvesting. Let dividends and interest land as cash, then deploy them where you are short. This is quietly powerful on a dividend-heavy portfolio.
• Spend from the overweight side. In retirement, take withdrawals from whatever has grown past target. That rebalances and funds your living costs in one move.
• Use maturing bonds. If you hold individual bonds, the cash from a maturity is already there to be redirected, which is one reason building a bond ladder makes rebalancing easier.

There is one more reason this matters for newer investors. Feeding money in steadily, as dollar-cost averaging does, means the direction of your contributions is doing quiet rebalancing work already.

9. Our rule for when to rebalance a portfolio

Quick Answer: Our verdict: look twice a year, trade only when something is more than 5 percentage points off target, and use new money before you sell. Adjust the band to 3 points once you are within five years of drawing on the money.

The last row is the one most readers belong in and least expect. Vanguard reported that 67% of its plan participants held a professionally managed option at the end of 2024, and only 5% placed a trade of their own. Those savers already rebalance a portfolio without a calendar reminder.

The 3-point band near retirement is a deliberate tightening. Late drift is expensive because there is no time to recover from it. We publish how we build every number so you can disagree with ours on the evidence.

10. Frequently Asked Questions

1. How often should I rebalance my portfolio?

Check once or twice a year and only trade when a holding is more than 5 percentage points off target. The SEC suggests reviewing every six to 12 months. Checking more often rarely helps, because Vanguard’s simulations found the gap between the best and worst rebalancing frequency was about 18 basis points a year.

2. What is the 5/25 rule for rebalancing?

It is a two-part drift band. Rebalance when a major holding moves 5 percentage points from its target, or when a smaller holding moves 25% of its own target size, whichever triggers first. So a 60% stock target acts at 65% or 55%, while a 10% gold sleeve acts at 12.5% or 7.5%.

3. Does rebalancing cost me money in taxes?

Only in a taxable brokerage account. Trades inside a 401(k), IRA or HSA create no tax bill at all. In a taxable account, selling shares held over a year triggers long-term capital gains tax of 0%, 15% or 20% federally in 2026. A 3.8% surtax lands on top once modified AGI passes $200,000 for a single filer.

4. Should I rebalance during a market crash?

Yes, if your drift band says so, and that is exactly when it will. A crash pushes the stock share below target, so rebalancing means buying stocks after they have fallen. That is uncomfortable and it is the whole point. A written rule decided in advance is what makes it possible to follow.

5. Do target-date funds rebalance automatically?

Yes. A target-date fund holds a set mix, shifts it gradually as the date approaches, and rebalances internally without you doing anything. Vanguard reported 67% of its plan participants in a professionally managed option at the end of 2024. Holding one alongside several other funds undoes the design.

This article is for general information and is not financial advice. See our full disclaimer.