How to Calculate Portfolio Rebalancing
What is Portfolio Rebalancing?
Portfolio rebalancing restores your target asset allocation after markets shift the proportions. It enforces buy-low/sell-high discipline and keeps your intended risk level consistent.
Formula
Rebalance when allocation drifts > 5% from target; Amount to rebalance = Current portfolio value × (Target % − Current %)
- Target
- Target asset allocation (Percentage)
- Current
- Current allocation (Percentage)
- Value
- Total portfolio value (Currency)
- Drift
- Allowable allocation drift (Percentage (typically 5%))
Step-by-Step Guide
- 1Compare current weights to target weights
- 2Sell over-weight; buy under-weight assets
- 3Rebalance annually or when any asset drifts > 5% from target
- 4Do it in tax-advantaged accounts to avoid capital gains
Worked Examples
Input
Target 60/40 stocks/bonds; stocks grew to 70%
Result
Sell ~10% of portfolio from stocks; reinvest in bonds
Frequently Asked Questions
How often should I rebalance?
Annually or quarterly if you have time. When allocation drifts > 5% from target. Frequent rebalancing (monthly) has tax/trading costs; annual is common.
Does rebalancing improve returns?
No, it locks in discipline and controls risk. Buy low, sell high naturally via rebalancing. Expected return same; volatility lower. Psychological benefit significant.
What are rebalancing costs?
Trading fees, tax on gains if selling appreciated assets. In tax-deferred accounts (401k), costs zero. In taxable, consider tax-loss harvesting while rebalancing.
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