A rebalancing band (or threshold) is a rule like: “Only trade when a sleeve is 5 percentage points away from its target.” If you want 60% stocks / 40% bonds, you act when stocks hit 65% or 55%—not when they drift to 61%. Bands sit beside calendar rebalancing (once or twice a year). Together they answer when to restore the mix you chose in Asset allocation basics.
Full tax-and-fee walkthrough: Rebalancing a portfolio. Beginner frame: Investing basics.
Calendar vs band vs both
| Rule | Trigger | Upside | Watch |
|---|---|---|---|
| Calendar | Birthday, New Year, tax season | Simple; limits tinkering | May trade when drift is tiny |
| Band / threshold | Sleeve ±3, ±5, or ±10 points off target | Trades only when risk actually moved | Needs a quick % check |
| Both | Check on a calendar; trade only if outside the band | Best of both for many DIY investors | Write the rule down |
| Target-date fund | Manager rebalances inside the fund | Hands-off (Target-date funds) | Still watch fees and glide path |
A 5-point band on a 60/40 mix is a common textbook starting point—not a promise of optimal returns. Narrow bands (2 points) mean more trades; wide bands (10 points) mean more drift.
Worked example: 5-point band on $100,000
Target: 60% stock index / 40% bond index at Vanguard, Fidelity, or Schwab.
| Date | Stocks | Bonds | Stock % | Action |
|---|---|---|---|---|
| Jan 1 | $60,000 | $40,000 | 60% | — |
| Apr 1 | $66,000 | $39,500 | 62.6% | Inside ±5 → no trade; optional: route new contributions to bonds (Dollar-cost averaging) |
| Oct 1 | $78,000 | $40,000 | 66.1% | Outside +5 → rebalance toward 60/40 |
At $118,000 total, 60/40 means $70,800 stocks and $47,200 bonds. Stocks are overweight by $7,200.
- Inside an IRA/401(k): sell $7,200 of stock fund, buy bond fund (no capital-gains tax from the trade itself inside the wrapper).
- In taxable: prefer new cash and dividends into bonds first; sell only if drift stays outside the band and the tax cost is acceptable (Taxable vs tax-advantaged; Capital gains basics).
How to set your band without obsessing
- Write the target mix (example 70/30 or 60/40) once.
- Pick a band (many households use 5 points on major sleeves).
- Pick a check date (quarterly glance is enough; trade only if outside the band).
- Prefer contribution-first rebalancing while you are still adding money.
- If you hold a single target-date fund, you do not need DIY bands on that account—the fund’s glide path already adjusts.
Multi-sleeve portfolios (U.S. stock / international / bonds) can use a band on each major sleeve or on stocks-vs-bonds as a group. Keep the rule simple enough that you will follow it after a noisy market week.
What bands are not for
- Day-trading noise inside a 1–2 point wiggle
- Changing your target because headlines feel scary (that is a new allocation decision, not rebalancing)
- Ignoring fees, bid-ask spreads, or short-term fund redemption fees (Brokerage fees; Expense ratios)
- Using bands to justify concentration in employer stock (Employer stock risk)
Checklist
- Write target weights for each major sleeve.
- Choose a band (for example ±5 percentage points).
- Choose a calendar check (quarterly or semiannual).
- On check day: compute current %; trade only if outside the band—or direct new money to the underweight side.
- Prefer IRA/401(k) trades when taxable gains would be large.
- Leave target-date-only accounts alone except for contribution rate and fee review.
Educational only. Not investment advice. Markets, taxes, and plan rules vary; verify trades against your account documents.