Finance & Money
Asset Allocation Drift Calculator
Apply separate period returns to equity, bonds, and cash, calculate the ending portfolio mix, and quantify the equity trade required to return to the entered target.
Ending equity value-
Ending bond value-
Ending cash value-
Ending portfolio value-
Ending equity share-
Equity allocation drift from target-
Equity trade to return to target-
Decision view
Return-driven allocation drift
Return-driven allocation driftSeparate asset-class returns explain the ending weight and exact rebalance amount.
Exact scenario comparisonEquity period return (%) changes while all other entered assumptions remain constant.
| Equity period return (%) | Ending equity value | Ending bond value | Ending cash value | Ending portfolio value | Ending equity share | Equity allocation drift from target | Equity trade to return to target |
|---|
How to use Asset Allocation Drift Calculator
- Use returns covering the same period for every class.
- Confirm opening holdings are complete.
- Compare percentage-point drift with the exact dollar rebalance.
Calculator guide
Understanding Asset Allocation Drift Calculator
Allocation drift occurs when asset classes earn different returns and finish the period at weights that no longer match policy targets.
Calculation method
How the calculation works
Apply separate period returns to opening equity, bond, and cash values, then calculate ending weights, drift, and the equity rebalance amount. Grow each opening class by its own entered return, divide ending equity by the ending portfolio, subtract the target share, and translate that drift back into dollars.
Drift anatomy
Trace the overweight position back to its source
Ending weights are easier to interpret when each asset-class return remains visible.
Worked situations
Practical examples
- Strong equity performance can raise equity weight even without new purchases.
- A negative bond return can increase equity share indirectly.
- Small percentage drift can represent a large trade in a large portfolio.
Better inputs
Useful tips
- Define tolerance bands in the investment policy.
- Measure all classes on the same date.
- Consider new contributions before selling.
Before relying on the result
Limitations and common mistakes
- One period and three broad classes are modeled.
- Cash flows, taxes, fees, intraperiod volatility, and multiple accounts are excluded.
- Only the equity target is entered explicitly.
Reference
Key terms
- Allocation drift
- Ending asset weight minus the entered target weight.
- Ending weight
- Ending class value divided by ending portfolio value.
- Rebalance amount
- Dollar trade required to restore the entered equity target.
- Tolerance band
- Policy range in which no rebalance may be required.
Important note
Calculated from the entered values and stated financial terms. It is not a product quote, lending decision, tax filing, or investment recommendation.
Frequently asked questions
Can equity drift upward if equity loses money?
Yes, if the other classes lose more.
Does the result include new contributions?
No.
Is any drift automatically a reason to trade?
No; policy tolerance bands and costs matter.
Why show a dollar rebalance amount?
It converts percentage drift into an actionable scale.