When should I rebalance my portfolio?
Last updated August 2026
Short answer
The frequency matters far less than the fact that it is a rule rather than a judgment call made while looking at a falling chart.
Calendar rebalancing
Pick a date, check the allocation, and correct it. Once a year is sufficient for most portfolios.
Its virtue is that it requires no monitoring, which means it actually happens.
Its weakness is that markets do not respect calendars, so a large move in March waits until the following January.
Threshold rebalancing
Set a band, such as five percentage points on a major asset class, and act when it is breached.
It responds to what markets actually do rather than to the date, so it corrects large moves promptly.
It requires checking periodically, which is a small cost now that reading an allocation takes seconds rather than a spreadsheet session.
The combined rule
Check on a fixed schedule, and rebalance only if drift exceeds the threshold.
That avoids trading in years when nothing much happened and catches the years when something did.
Writing it down matters more than which variant you choose, because a rule that exists only in your head is a judgment call wearing a costume.
Try it in Walnut
Walnut connects to your brokerage and shows what your allocation has actually drifted to, which is the number the rule needs.
Rebalancing without selling
Direct new contributions into whatever is underweight, which corrects drift with money that was going in anyway.
Switch off automatic dividend reinvestment, so distributions arrive as cash you can point at the laggard.
Do any selling inside retirement accounts first, where it creates no taxable event.
The hardest time to follow it
After a large decline, the rule says buy more equities, which is precisely when nobody wants to.
After a long run-up, it says trim the winners, which feels like cutting the flowers.
Both discomforts are the mechanism working, and they are the reason the rule is set in advance rather than debated in the moment.
What to check while you are there
Drift inside an asset class, not only between classes: an equity allocation at exactly target can still be concentrated in a handful of companies.
Overlap between funds, which quietly increases exposure without changing any label.
Whether the target still matches your horizon, since a mix set a decade ago may no longer fit.
Tax makes the answer different in each account
Inside a 401(k), IRA or HSA there is no tax consequence to selling, so the rule can be followed exactly.
In a taxable account, selling an appreciated position realises a gain, so the same rule is applied through contributions and dividends wherever possible.
The practical approach for someone holding both is to do the correcting inside the sheltered accounts first, and only sell in the taxable one when the drift cannot be closed any other way.
Sources
Guidance on asset allocation, diversification and rebalancing is published by the SEC at investor.gov. Capital gains treatment on sales is in IRS Topic no. 409. Walnut is informational and is not an investment adviser. This guide is educational and not personalized investment advice.
FAQ
How often should I rebalance?
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Once a year on a fixed date, or whenever an allocation drifts more than a set threshold such as five percentage points. Both are defensible and neither requires any view about markets.
Is more frequent rebalancing better?
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No. Checking monthly generates trades, costs and in a taxable account tax, without improving the outcome. The evidence does not support frequent adjustment, and the discipline is easier to keep at a lower frequency.
Should I rebalance during a crash?
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That is when the rule earns its keep, because after a fall the equity share is below target and the rule says buy. Having set the trigger in advance is what makes the action possible at the moment it feels worst.
What threshold should I use?
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Five percentage points on a major asset class is a common choice, or a relative band such as 25% of the target weight. The specific number matters less than having one written down before you need it.
Can I rebalance without selling?
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Frequently, yes. Directing new contributions into whatever is underweight, and taking dividends as cash rather than reinvesting them, corrects drift without a single sale or a single taxable event.
Does it improve returns?
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Not reliably. Over long rising periods, trimming winners can slightly reduce return. The purpose is keeping risk at the level you chose, which is a different objective from maximising it.
What about target-date funds?
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They rebalance internally, so there is nothing to do inside them. Holding one alongside other funds still leaves your overall allocation drifting, which is the level that needs checking.
What if my target itself is wrong?
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Then change the target, which is a separate decision from rebalancing to it. Conflating the two turns every rebalance into a fresh argument about strategy, which is how the discipline breaks down.
Does it matter which account I rebalance in?
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Considerably. Selling inside a 401(k), IRA or HSA creates no taxable event, so the rule can be followed exactly there. In a taxable account, do the correcting with new contributions and dividends first and sell only when drift cannot be closed any other way.