Key Takeaways
- Rebalancing means adjusting your investments back to your target mix after some holdings grow faster than others.
- Without it, strong performers quietly make your portfolio riskier than you intended.
- Most investors only need to rebalance once a year, or when an allocation drifts more than about 5 percentage points from target.
- The easiest way to rebalance is by directing new contributions—buying more of what’s lagged—rather than selling.
You set your portfolio to a sensible mix—say 70% stocks, 30% bonds—and then walk away. A few strong years later, stocks have surged, and your portfolio is now 80% stocks, carrying more risk than you signed up for. Rebalancing fixes that drift. This article explains what rebalancing is, how to do it, how often you actually need it, and why the low-effort approach usually wins.
The reassuring news: rebalancing is one of the least demanding parts of investing. Done right, it’s a quick annual check-in, not a constant chore.
What rebalancing is and why it matters
Your asset allocation—the split between stocks, bonds, and other assets—is the main lever controlling your portfolio’s risk. Over time, different assets grow at different rates, so your allocation drifts away from your target. Because stocks usually grow faster than bonds, the drift almost always makes your portfolio more stock-heavy and therefore riskier.
Rebalancing means selling a bit of what has grown too large and buying more of what has shrunk, returning to your intended mix. It’s a disciplined way of “buying low and selling high” automatically—trimming winners and topping up laggards.
“Rebalancing forces you to do the emotionally hard thing: sell some of what’s been winning and buy what’s been losing. That’s precisely why it works.”
How to rebalance, step by step
The process is straightforward:
- Know your target. Write down your intended allocation, e.g., 70% stocks / 30% bonds.
- Check your current mix. Look at what percentage each asset actually represents now.
- Compare and adjust. If stocks have drifted to 78%, sell enough to bring them back to 70% and move the proceeds into bonds—or, better, direct new contributions toward the underweight asset.
- Mind the taxes. In a tax-advantaged account (401(k), IRA), selling to rebalance has no immediate tax cost. In a taxable account, prefer rebalancing with new contributions to avoid triggering capital gains.
How often should you rebalance?
Here’s where many people overthink it. You do not need to rebalance constantly—doing so can increase costs and taxes for little benefit. Two common, sensible approaches:
Time-based: check once a year (some do twice) and rebalance if needed. A birthday or year-end is an easy reminder.
Threshold-based: rebalance only when an allocation drifts more than a set amount—often about 5 percentage points—from its target. Many investors combine the two: check annually, but only act if something has drifted meaningfully. The evidence suggests the exact method matters less than simply having one and sticking to it.
The easiest method: rebalance with new money
If you’re still contributing regularly, you often don’t need to sell anything. Simply direct your new contributions toward whichever asset has fallen below target. Adding fresh money to the laggard nudges your allocation back toward its goal without realizing any gains or paying taxes. For many everyday investors, this “cash-flow rebalancing” quietly keeps the portfolio in line with minimal effort.
A quick case study: the once-a-year check-in
Consider Priya, who holds a 75% stocks / 25% bonds target. After a strong market year, her portfolio has drifted to 82% stocks. At her annual December review, she notices the 7-point gap exceeds her 5-point threshold. Rather than sell (her holdings are in a taxable account), she redirects her January contributions entirely into bonds for a few months and pauses her automatic stock purchases until the mix returns to 75/25.
No taxable sales, no drama—just a small, deliberate adjustment once a year. Her neighbor, who never rebalances, has unknowingly drifted to 90% stocks and will feel a much harder hit in the next downturn. (This is general information, not personalized investment advice.)
A note on target-date funds
If you hold a target-date fund, good news: it rebalances itself automatically. The fund maintains its allocation and gradually shifts toward bonds as you age, so you never have to do any of this manually. That built-in discipline is a big part of why target-date funds are such a popular one-stop option.
Frequently asked questions
What does it mean to rebalance a portfolio?
It means adjusting your investments back to your target allocation after market movements shift the balance—typically trimming assets that grew too large and adding to those that shrank —so your risk level stays where you intended.
How often should I rebalance?
For most investors, once a year is plenty, or whenever an allocation drifts more than about 5 percentage points from target. Rebalancing more often usually adds cost and taxes without meaningful benefit.
Do I have to sell investments to rebalance?
Not necessarily. If you’re still contributing, you can often rebalance by directing new money toward whatever asset has fallen below target. This avoids selling and, in a taxable account, avoids triggering capital gains.
Does a target-date fund need rebalancing?
No—it rebalances automatically and shifts its mix toward bonds as you approach retirement. That hands-off maintenance is one of the main advantages of using a single target-date fund.
Image Credit: RDNE Stock project, Pexels
