What rebalancing means and why it matters

Rebalancing means selling some of the investments that have grown larger than you intended and buying more of the ones that have shrunk, so your portfolio matches your original plan again. Over time, your winners grow faster than your losers, which shifts the risk you are actually taking without you noticing. Rebalancing brings you back to the mix you chose.

If you started with 60% stocks and 40% bonds, and stocks have risen so much that you now hold 70% stocks and 30% bonds, you are taking more risk than you meant to. A market downturn hits harder. Rebalancing forces you to sell high and buy low — the opposite of what most people do naturally, and the reason it works.

You do not need to rebalance constantly. Most people do it once a year, or when one part of their portfolio drifts more than 5 percentage points away from the target. Some do it only when they add new money. The point is to have a plan and stick to it, not to chase performance.

Key Takeaways

  • Rebalancing means selling investments that have grown too large and buying ones that have shrunk, to match your original target mix.
  • A common trigger is when any part of your portfolio drifts more than 5 percentage points from your target — for example, stocks rising from 60% to 65%.
  • You can rebalance by selling winners and buying losers, or by directing new contributions toward the underweight parts.
  • Tax-advantaged accounts like 401(k)s and IRAs have no tax cost when you rebalance, but regular brokerage accounts may trigger capital gains taxes.
  • Set a rebalancing schedule — annual, quarterly, or when drift hits a threshold — and follow it without trying to time the market.

Decide on your target allocation

Before you can rebalance, you need to know what you are rebalancing toward. Your target allocation is the percentage of your money in each type of investment: stocks, bonds, real estate, cash, or whatever else you hold. This should match your time horizon, risk tolerance, and financial goals — the same factors that guided your original choice.

A common starting point is your age. Some people use "110 minus your age" or "120 minus your age" as the percentage to hold in stocks, with the rest in bonds. A 40-year-old using the first rule would hold 70% stocks and 30% bonds. A 60-year-old would hold 50% stocks and 50% bonds. These are rules of thumb, not rules. Your actual target depends on your situation.

Write down your target allocation in percentages. If you hold individual stocks, bonds, and a money market fund, decide what percentage of your total portfolio each should be. If you hold mutual funds or exchange-traded funds (ETFs), decide what percentage each fund should represent. The more specific you are, the easier rebalancing becomes.

Calculate what you actually hold right now

Pull up your account statements or log into your brokerage portal. Add up the current value of every holding — every stock, fund, bond, and cash position. Then divide each holding's value by your total portfolio value to get the percentage it represents today.

Example: You have $100,000 total. You hold $60,000 in a stock index fund, $30,000 in a bond fund, and $10,000 in cash. That is 60% stocks, 30% bonds, and 10% cash. If your target was 60% stocks, 35% bonds, and 5% cash, you are overweight in stocks and cash, and underweight in bonds.

Do this calculation for every holding. If you own 20 individual stocks, calculate the percentage each represents. If you own funds, calculate the percentage each fund represents. Spreadsheets make this easier, but pen and paper works too. The goal is to see exactly where you stand.

Identify which holdings are out of line

Compare what you actually hold to your target. Look for holdings that have drifted more than a few percentage points in either direction. A common rule is to rebalance when any holding drifts 5 percentage points or more from its target.

Using the earlier example: your stock fund is at 60% and your target is 60%, so it is in line. Your bond fund is at 30% but your target is 35%, so it is 5 percentage points underweight. Your cash is at 10% but your target is 5%, so it is 5 percentage points overweight. Both the bond fund and cash have crossed the threshold.

Some people use a tighter threshold (3 percentage points) and rebalance more often. Others use a looser one (10 percentage points) and rebalance less often. Tighter thresholds keep you closer to your target but generate more trading and, in taxable accounts, more taxes. Looser thresholds mean less trading but more drift. Choose what fits your situation.

Decide whether to sell and buy, or redirect new money

You have two main ways to rebalance. The first is to sell some of your overweight holdings and use the proceeds to buy underweight ones. The second is to direct any new money you add toward the underweight holdings until they catch up.

Selling and buying works when ready but can trigger capital gains taxes in a regular brokerage account. If you have held a winning stock for years and it has grown a lot, selling it means paying tax on the gain. Redirecting new money avoids this tax cost but takes longer — you have to wait until you have new money to invest, and the rebalancing happens gradually.

In tax-advantaged accounts like 401(k)s and traditional IRAs, you can sell and buy without any tax consequence, so rebalancing is free. In regular brokerage accounts, consider the tax cost before you sell. If the tax bill is large and you can wait, redirecting new money may be smarter. If you have little new money coming in, or if the tax cost is small, selling and buying may be faster.

Execute the trades in your account

Log into your brokerage account. If you are selling, place a sell order for the overweight holdings. Specify how many shares you want to sell, or the dollar amount. Most brokerages let you choose either. Once the sale settles (usually one to two business days), the cash appears in your account.

Then place a buy order for the underweight holdings using the cash from your sale. Buy enough to bring each underweight holding back to its target percentage. If you are redirecting new money instead, straightforward direct that money into the underweight holdings when you add it.

Some brokerages offer automatic rebalancing tools that do this for you on a schedule you set. If your brokerage offers this and you trust the settings, it removes the need to remember to rebalance. Check your account settings or call your brokerage to see if this is available.

Set a rebalancing schedule and stick to it

Decide in advance how often you will rebalance. Common choices are once a year (often at the start of the year or on your birthday), once a quarter, or whenever any holding drifts more than 5 percentage points from its target. Write this down or set a calendar reminder.

The point of a schedule is to remove emotion from the decision. If you rebalance only when you feel like the market is about to turn, you are trying to time the market — and most people are bad at it. A schedule forces you to sell winners when they are high and buy losers when they are low, which is the opposite of what feels comfortable and the reason it works.

Do not rebalance constantly. Trading costs money in commissions and spreads, and in taxable accounts, it costs money in taxes. Once a year is a reasonable default. If you are adding money regularly (like monthly contributions to a 401(k)), you can rebalance by directing new money toward underweight holdings and skip the selling step entirely.

Frequently Asked Questions

What if I have money in both a 401(k) and a regular brokerage account?

Rebalance each account separately. Calculate your target allocation across all your accounts combined, then figure out what each account should hold to match that overall target. This lets you use the tax-free rebalancing in your 401(k) to offset the tax cost in your brokerage account, or to avoid selling winners in the brokerage account altogether.

Do I have to rebalance if my portfolio is doing well?

Yes. A portfolio that is doing well is usually the one that is most out of balance — your winners have grown so large that you are taking more risk than you intended. Rebalancing forces you to trim the winners and buy the losers, which is uncomfortable but necessary to stay on track.

What if rebalancing would trigger a huge capital gains tax?

You have options. You can redirect new contributions toward underweight holdings instead of selling. You can rebalance only in tax-advantaged accounts and leave your taxable accounts alone. You can spread the rebalancing over several years, selling a little bit each year. Or you can accept the tax bill as the cost of staying on track. Talk to a tax professional if the amount is large.

How do I rebalance if I own individual stocks instead of funds?

Calculate what percentage of your portfolio each stock represents. If one stock has grown to 15% of your portfolio and your target was 10%, sell enough shares to bring it back to 10%. Use the proceeds to buy shares of underweight stocks or funds. The process is the same; you just have more holdings to track.

Can I rebalance inside a 401(k) without paying taxes?

Yes. Selling and buying inside a 401(k) or traditional IRA generates no tax consequence because the account itself is tax-deferred. You can rebalance as often as you want without worrying about capital gains taxes. This makes tax-advantaged accounts the best place to rebalance aggressively if you need to.