How Often Should I Rebalance My 401(k)? Calendar vs. Threshold

You absolutely can leave your portfolio untouched alone for long stretches of time. In fact, doing less is often better than doing more.

But that doesn’t mean you should never check whether your investments still match the level of risk you intended to take.

Rebalancing simply means bringing your portfolio back to its original target allocation.

• If stocks exceed their target allocation, sell some and buy underweighted assets
• If bonds have become too large a portion of your portfolio, you do the opposite.

Calendar vs. Threshold 401(k) Rebalancing

There are two common ways to rebalance a portfolio.

1. Calendar Rebalancing

Basically, you choose a date, perhaps every January, every June, or every quarter, and review your portfolio on that schedule.

If your allocation has drifted, you make adjustments.

You don’t have to think about market movements or monitor your account every week. You simply follow the calendar.

2. Threshold Rebalancing

Instead of using dates, you rebalance when an asset class moves a certain distance from its target allocation.

Suppose your target allocation is 60% stocks. You might decide to rebalance whenever stocks rise above 65% or fall below 55%.

In that case, the market, not the calendar, determines when action is required.

Many investors use a threshold of roughly 5 percentage points, although some prefer wider bands.

What about a Hybrid Approach?

You review your portfolio once or twice a year, but only make changes if allocations have drifted beyond a predetermined threshold.

Whichever method you choose, you need to be consistent and keep your portfolio’s risk profile consistent, while not overtrading on every minor market move.

What’s the best method?

Probably whichever one you’ll actually follow.

How Often Should You Rebalance? Annual vs. More Often?

For most investors, annual rebalancing is probably enough.

• Semiannual reviews can also make sense if you prefer checking your portfolio twice a year.
• Quarterly reviews are common as well, especially among investors who like a little more oversight.

But once you move into monthly reviews, the benefits are not worth it.

Let’s consider a hypothetical investor (who is you) with a $500,000 portfolio.

If your target allocation is 60% stocks and 40% bonds, a strong stock market might push that allocation to 64% stocks and 36% bonds.

Would I rush to rebalance?

Probably not.

The portfolio hasn’t drifted dramatically. The risk profile is still reasonably close to the original target.

On the other hand, if stocks climbed to 70% of the portfolio, I’d be much more inclined to make adjustments.

At that point, the portfolio has become something meaningfully different from what the investor originally intended to own.

That’s why many investors, and even I personally, prefer to combine an annual review with a simple 5% drift rule (when needed).

Should You Set It On Auto-Rebalancing?

Of course, not everyone needs to rebalance manually. Many target-date funds handle the process automatically.

If you’re invested entirely in a target-date fund, the fund manager is already maintaining the allocation and gradually adjusting it as retirement approaches.

In that situation, additional rebalancing is usually unnecessary.

The same is true for many

• Managed-account and
• Auto-rebalancing programs.

When Should You Rebalance Outside Your Schedule?

Most of the time, sticking to a predetermined schedule works fine.

1. Major Life Events

Major life changes can alter your investment goals or risk tolerance.

• Marriage/divorce
• New child
• Inheritance
• Career change, or
• A shift toward retirement may call for revisiting your asset mix.

2. Large Market Moves

If a dramatic rally leaves stocks heavily overweight, or a major decline significantly changes your asset mix, a review may be worthwhile even if your scheduled rebalance date is months away.

3. Contributions and Withdrawals

Regular 401(k) contributions can themselves rebalance a portfolio.

Imagine your bond allocation has fallen below target.

Instead of selling stocks, you could direct future 401(k) contributions into bond funds until the portfolio gradually moves back toward your desired allocation.

Why Rebalancing is Important?

Let’s look at a simple example. Suppose you started with a portfolio that was

• 60% stocks and
• 40% bonds.

After several strong years in the stock market, your allocation drifts to

• 70% stocks and
• 30% bonds.

Many investors would look at those numbers and do nothing. After all, their account balance is growing.

But the portfolio they’re holding today is considerably riskier than the portfolio they originally chose.

That’s exactly what rebalancing is designed to fix, and in fact, annual reviews appear to work surprisingly well, too.

401(k) Rebalancing FAQs

Do I Need To Rebalance My 401(k) Every Year?

Generally yes, most investors rebalance at least once a year because portfolios drift over time, although small changes may not require immediate action if your allocation is still close to target.

Can I Use My Regular Contributions Instead Of Selling Investments?

Yes, you can rebalance by directing new contributions into underweighted funds instead of selling existing holdings, which is a simple way to adjust your allocation without triggering taxes or trading costs inside a 401(k).

Isn’t Rebalancing Just Moving Money Around? Will It Really Help?

Yes, but it matters because it keeps your portfolio aligned with your risk level and naturally enforces a “buy low, sell high” discipline, which can improve long-term risk-adjusted returns.

What If There’s A Big Market Crash?

During a sharp market drop, your allocation can shift significantly, and rebalancing may help restore your target mix, but it’s usually best done systematically rather than reacting emotionally to short-term volatility.

Will Frequent Rebalancing Hurt My Returns?

Not in a meaningful way inside a 401(k), but doing it too often rarely adds value, and most research shows that annual or periodic rebalancing performs very similarly to more frequent adjustments.

What Rebalancing Threshold Should I Use?

A common approach is to rebalance when your allocation drifts about 5% from your target, although the exact number is flexible and the key is to apply the same rule consistently over time.

Are There Transaction Costs Or Taxes In A 401(k)?

Usually no taxes apply inside a 401(k), and most plans also allow internal fund exchanges with little or no trading cost, making rebalancing relatively straightforward compared to taxable accounts.

Should I Rebalance My Target-Date Fund Or LifeStrategy Fund?

No, these funds already rebalance automatically and adjust your allocation over time, so manual rebalancing is generally unnecessary and can interfere with their intended glide path.

How Does Rebalancing Fit With Tax-Loss Harvesting Or Other Strategies?

Tax-loss harvesting does not apply in a 401(k), so rebalancing here is simply about maintaining your asset allocation rather than managing taxes or realized losses.

Is It Really Worth Doing If I Have Small Balances?

Yes, even small accounts benefit from staying close to your target allocation, and in many cases a simple annual check or contribution-based adjustment is all that’s needed.

References:

• https://www.fidelity.com/learning-center/trading-investing/rebalance
• https://www.schwab.com/learn/story/rebalancing-action