Start with the objective
Rebalancing moves holdings toward a chosen allocation. That is an exposure-management objective, separate from maximizing a future return. Holding a growing winner can produce a higher return in one path while leaving more concentration. Selling it can reduce that concentration and still reduce the eventual return. Neither observation establishes a universal winner.
A two-asset example you can check
Suppose two holdings begin at 5,000 each. A doubles to 10,000 while B stays at 5,000. Total value is 15,000 and A is now 66.67%, rather than its original 50%. Restoring equal weights, ignoring costs, sells 2,500 of A and buys 2,500 of B.
If A then rises another 20% and B is unchanged, the rebalanced portfolio reaches 16,500; the untouched portfolio reaches 17,000. If A instead falls 20%, the respective totals are 13,500 and 13,000. These are alternative invented paths from the same decision point, not historical evidence or equally likely outcomes.
Consider alternatives to selling
New contributions can be directed to an underweight holding. Withdrawals can sometimes be taken from an overweight one. Neither method necessarily restores a target immediately. Assess the actual cash flow, available assets and account restrictions before assuming that a trade is required.
Compare a policy, not an isolated winning trade
Write down the target, review interval, drift definition and execution rule. Compare policies on identical data and cash flows, counting spread, commission, financing and any relevant tax. Include changes in exposure, drawdown, turnover and ending wealth. A portfolio that ends richer with much greater concentration has not been shown to deliver the same risk.
A defensible study identifies its dataset, dates, assets, delistings and parameter selection. This publication does not possess a reproducible record supporting the previous article’s specific return comparisons, so those numbers have been removed.
Questions to answer before an adjustment
- Does the target still reflect the intended exposure and time horizon?
- How far has the allocation moved, measured consistently?
- Can cash flows reduce the drift?
- What costs and taxable realizations would a sale create?
- What would invalidate the policy, rather than merely make a trade look bad afterward?
Sources and scope
References support the stated definitions or research context. The worked examples on this page use invented inputs and do not reproduce a market study. Source checks: 16 October 2026.
Continue with a practical tool
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