Why trust this guide: the method below comes from Investor.gov and Fidelity's published guidance. The dollar figures are a made-up worked example, not a forecast. We show no return numbers because none can be promised.
Rebalancing means selling a little of what has grown too big in your portfolio and buying more of what has shrunk, so your mix of stocks and bonds matches the plan you chose. Think of it as a yearly tune-up. Left alone, a portfolio drifts toward whatever has been winning, and that usually means more risk than you signed up for.
The good news: for most beginners, rebalancing takes about 20 minutes once or twice a year. Some people never have to sell anything at all.
What does it mean to rebalance a portfolio?
Rebalancing is adjusting your investments back to your target asset allocation after market moves push them off course. Investor.gov gives a simple example: a portfolio that starts at 80 percent stocks and 20 percent bonds drifts to 85/15 after a year, so you sell some stocks and buy bonds to get back to 80/20.
Your target allocation is the split you picked on purpose, such as 70% stocks and 30% bonds. Drift is how far you've wandered from it. Rebalancing closes the gap.
Why bother? Because your stock share is your risk dial. If you wanted a calm 70/30 portfolio and quietly became an 80/20 one, a bad year for stocks will hurt more than you planned for. Rebalancing also nudges you to trim winners and add to laggards, which is the boring version of "buy low, sell high."
How often should you rebalance?
Investor.gov says many investment professionals recommend rebalancing regularly, typically every six to 12 months. Fidelity describes three common approaches, and any of them works if you stick to it.
| Approach | How it works | Best for |
|---|---|---|
| Calendar | Rebalance on a fixed date, such as every January | People who want a simple habit |
| Threshold | Rebalance when any piece drifts 5 percentage points or more (Fidelity's example) | People who like rules over dates |
| Hybrid | Check quarterly, act only if drift passes your threshold | People who check often but want fewer trades |
How to rebalance your portfolio (step by step)
1. Write down your target mix
You can't rebalance toward a target you never set. Choose your stock-to-bond split based on your timeline and how much of a drop you can stomach. If you haven't chosen one, our beginner investing mistakes guide is a good place to start. For this example we'll use 70% stocks and 30% bonds.
2. Add up what you actually hold
Open every account you invest in. Include your 401(k), IRA and any taxable brokerage account. Total the stock funds and bond funds across all of them. Rebalancing works on the whole picture, not one account at a time.
3. Find the drift
Divide each holding by your total. Compare it to your target. If you're within a few points, you can stop here and do nothing. Doing nothing is a valid result.
4. Choose how to close the gap
You have two tools: sell and buy, or steer new money. Fidelity notes that directing new contributions toward the investments that are too small restores balance without selling anything. We walk through both below.
5. Write down the date and what you did
One line in a notes file is enough. Next time, you'll know when the clock restarts.
A worked example, in dollars
Here is the math with made-up numbers. Assume you start with $10,000: $7,000 in a stock index fund and $3,000 in a bond fund (70/30). Over the year, stocks rise 20% and bonds stay flat. That is an assumption, not a prediction.
| Stocks | Bonds | Total | Mix | |
|---|---|---|---|---|
| Start | $7,000 | $3,000 | $10,000 | 70 / 30 |
| After a year | $8,400 | $3,000 | $11,400 | 73.7 / 26.3 |
| Target at $11,400 | $7,980 | $3,420 | $11,400 | 70 / 30 |
| Move needed | Sell $420 | Buy $420 |
Now the no-sell version. Suppose you also have $1,000 to invest this year. Your new total is $12,400, so the target is $8,680 in stocks and $3,720 in bonds. You already hold $8,400 in stocks, so you buy $280 of stocks and $720 of bonds. You are back at 70/30 and you sold nothing.
Do you pay taxes when you rebalance?
It depends on the account. Fidelity explains that rebalancing inside tax-advantaged accounts such as 401(k)s, IRAs, HSAs and 529s creates no tax consequences. In a taxable brokerage account, selling at a profit can trigger capital gains tax.
That is why the order matters. Rebalance inside your retirement accounts first, where trades are tax-free. In taxable accounts, steer new money before you sell. Investor.gov also warns to watch for fees and tax implications, because they can outweigh the benefit of a small rebalance. If you're deciding between account types, see brokerage account vs. Roth IRA.
Do you even need to rebalance?
Sometimes you don't, because something else does it for you. Investor.gov mentions target-date or lifecycle funds, which automatically adjust the mix as you age. Robo-advisors also rebalance for you, usually for a fee. Compare the trade-offs in are target-date funds worth it and robo-advisor vs. index funds.
Regular contributions help too. If you invest every paycheck, like in dollar-cost averaging, you can point new money at whichever piece is behind. Many people rebalance this way for years.
Common mistakes
- Rebalancing too often. Trading every month adds costs and taxes for little benefit. Once or twice a year is plenty.
- Checking one account, not the whole portfolio. Your 401(k) might be heavy in stocks while your IRA is all bonds. Look at the total.
- Selling in a taxable account without checking the tax. Steer new money first.
- Rebalancing out of fear. Dumping stocks after a drop isn't rebalancing. It's panic. Rebalancing means following a rule you set when you were calm.
- Never setting a target. With no target, there's nothing to rebalance toward.
- Ignoring fees. If a fund charges a fee to trade, factor it in. See investing fees that eat your returns.
Edge cases
Irregular income: Your contributions may be lumpy. Use a calendar rule, and when a big payment arrives, put it into whatever is furthest below target.
Tight budget: With a few hundred dollars invested, the drift is tiny. A yearly check is enough, and steering new money does the job. Start with investing $100 if you haven't yet.
Starting from zero: You don't need to rebalance until you have a mix to rebalance. Buy a simple first index fund and set your target.
A big market swing: If stocks fell hard, your stock share is below target, and rebalancing means buying stocks. That feels scary, which is exactly why a written rule helps.
Who should skip this
Skip manual rebalancing if you hold a single target-date fund or use a robo-advisor, because the mix is handled for you. Skip it, too, if your portfolio is tiny and you're adding money regularly; new contributions will do the work. And don't rebalance in a taxable account if the tax bill would wipe out the benefit. Keep saving instead. A zero-friction automatic plan often beats clever tweaking.
Quick answers
What is rebalancing in simple terms? It's selling some of what grew too large and buying more of what fell behind, so your portfolio matches the stock-to-bond mix you chose.
How often should I rebalance? Investor.gov says many professionals suggest every six to 12 months. Fidelity also describes rebalancing when a holding drifts about 5 percentage points from its target.
Does rebalancing cost money? It can. Trades may carry fees, and selling in a taxable account can trigger capital gains tax. Rebalancing inside retirement accounts has no tax consequences, according to Fidelity.
Can I rebalance without selling anything? Yes. Direct new contributions to the investments that are below target. Fidelity notes this avoids taxable events in brokerage accounts.
Do target-date funds rebalance automatically? Investor.gov says target-date and lifecycle funds automatically adjust their mix as you age. Check the fund's details to see how it does this.