Portfolio rebalancing is the act of returning your investments to their intended mix after market moves have pushed them off target. Say you planned to hold 70 percent stocks and 30 percent bonds; after a strong stock run you might find yourself at 80 and 20. Rebalancing means selling a bit of the part that grew and buying the part that shrank, so you are back near 70 and 30. The point is risk control, not boosting returns. It keeps a portfolio from quietly becoming riskier than you intended. This is general educational information, not personalized investment advice, so verify the right approach for your own situation.
Why portfolios drift
Different assets grow at different rates. Over time, the best performers take up a larger and larger share, which sounds good but raises your risk. A portfolio that drifts to mostly stocks will fall harder in a downturn than the mix you actually signed up for. Rebalancing is how you trim that creeping risk back to plan. The target itself comes from your asset allocation, so rebalancing only makes sense once you have set one.
The main methods
| Method |
How it works |
Best for |
| Calendar |
Rebalance on a fixed schedule, often yearly |
Simplicity and discipline |
| Threshold |
Rebalance when a holding drifts past a set band |
Reacting to big market moves |
| Hybrid |
Check on a schedule, act only if past the band |
Reducing needless trades |
| Cash-flow |
Steer new contributions toward the lagging asset |
Avoiding sales and taxes |
The cash-flow approach is often the gentlest: by directing new money into whatever is underweight, you nudge the mix back without selling anything, which sidesteps taxes in a regular account.
How to rebalance, step by step
- Know your target. Write down the percentages you intend to hold across stocks, bonds, and anything else.
- Check current weights. Compare today actual percentages to the target.
- Decide if it is worth acting. If a holding has drifted past your chosen band, plan a trade; small drifts can wait.
- Prefer new money first. Direct fresh contributions to the underweight asset before selling anything.
- Mind the account type. Selling inside a tax-advantaged account usually has no immediate tax cost; selling in a regular account may trigger taxes.
What to skip
- Rebalancing too often. Frequent trades can rack up fees and, in taxable accounts, taxes that outweigh the benefit.
- Chasing performance. Rebalancing is mechanical and unemotional by design; do not abandon it to pile into whatever just rose.
- Ignoring taxes. In a regular brokerage account, selling winners can create a tax bill, so favor cash-flow rebalancing or tax-advantaged accounts where possible. Always confirm tax effects for your situation.
FAQ
How often should I rebalance?
There is no single right answer. Many long-term investors check about once a year or when a holding drifts past a set threshold. Pick a rule and stick to it.
Does rebalancing increase my returns?
Not reliably. Its primary job is keeping risk near your target, not generating extra return. Sometimes it helps returns, sometimes it slightly trims them.
Do robo-advisors rebalance for me?
Many do, automatically. If you prefer a hands-off approach, see the robo-advisor explainer below.
Will rebalancing cost me taxes?
It can, if you sell appreciated assets in a taxable account. Rebalancing inside tax-advantaged accounts or with new contributions avoids that. Verify your own tax situation.
Where to go next
Learn what asset allocation is, see what a robo-advisor does, and build an investment strategy.