The big picture
A portfolio’s allocation changes even when you place no trades. Rebalancing connects today’s holdings with the risk you intended to take. This topic explains how to measure the change, decide whether action is justified and implement the decision with a clear audit trail.
Core concepts
Learning objectives
- Calculate weights and percentage-point drift.
- Choose a review rule appropriate to the goal.
- Use contributions and withdrawals before unnecessary trades.
- Document costs, triggers and policy overrides.
Define a target allocation before trading
1.1 Goals and risk capacity
Rebalancing restores a chosen risk allocation after market moves, cash flows or life changes. It begins with a target, not with selling whatever has risen most. Define the purpose of the portfolio, the horizon, essential cash needs and the size of loss you could financially withstand. Willingness to take risk and capacity to bear it can differ considerably. A person may feel comfortable with volatility but still need the money for a near-term payment.
1.2 Allocation ranges and constraints
Write allocation ranges that reflect the underlying exposures rather than only account names. An equity fund and directly held shares can both occupy the equity allocation. The target should identify country, sector, issuer and currency constraints where relevant. No fixed percentage is suitable for every investor. A target that cannot be funded, monitored or followed through a decline is unlikely to be an effective policy.
Step-by-step method
- State the portfolio goal and spending horizon.
- Identify non-negotiable liquidity needs.
- Write target weights and permitted ranges.
A household separates next year’s education payment before designing its long-term equity allocation. Rebalancing is then judged against two different purposes instead of one misleading blended balance.
Measure drift with consistent values
2.1 Market values and cash balances
An asset’s current weight equals its current market value divided by total portfolio value on the same date. Include the cash and exposures covered by the policy and identify unsettled obligations separately. Mixing a fund valuation from one day with a share price from another can create an artificial drift. Record valuation dates, currencies and whether an amount is restricted or available.
2.2 Percentage points versus percentages
Weight drift in percentage points is current weight minus target weight. Relative drift divides that difference by the target weight; these are different measures and need different thresholds. For example, a hypothetical move from 40% to 50% is ten percentage points, or 25% relative drift. Use one defined method rather than changing the rule to justify an attractive-looking trade.
Step-by-step method
- Value all covered holdings on one consistent date.
- Calculate each current weight and its drift.
- Separate percentage-point drift from relative drift.
Teaching example: a PKR 1,000,000 portfolio has PKR 700,000 equities and PKR 300,000 other assets. A 60/40 policy implies PKR 600,000 and PKR 400,000; the required adjustment is PKR 100,000 before costs and taxes.
Choose a review trigger that you can follow
3.1 Calendar and threshold approaches
A calendar policy reviews allocation at planned intervals. A threshold policy reacts when drift exceeds a defined band. A combined policy checks periodically but trades only when a band is breached or a material life event occurs. Each approach trades off monitoring effort, transaction cost and the risk of allowing exposures to move too far. None reliably identifies market tops or bottoms.
3.2 Structural change versus normal noise
Distinguish allocation drift from a broken investment thesis. A company whose financial resilience deteriorates does not automatically deserve a larger position merely because its price has fallen. Before buying to restore a weight, ask whether the original holding remains suitable. A material change in income, liabilities or required spending may call for a new target rather than a return to the old one.
Step-by-step method
- Select a review frequency and explicit bands.
- Define life events requiring a policy review.
- Recheck suitability before adding to a fallen position.
An investor’s employment becomes uncertain while equity prices rise. The cash need changes independently of market drift; the review may properly revise the policy before any rebalancing trade.
Implement with cash flows, costs and liquidity in mind
4.1 Contributions before forced sales
New contributions and available distributions can often be directed toward underweight exposures, reducing the amount that must be sold. Withdrawals can sometimes come from overweight positions. These techniques reduce turnover but are not always sufficient, especially if the portfolio is large relative to incoming savings. Calculate the adjustment after allowing for actual cash flows rather than assuming that trades are the only tool.
4.2 Taxes, spreads and execution
Before trading, estimate brokerage, statutory charges, bid–ask spread, market impact and applicable tax consequences from verified records. A small drift may not justify a large execution cost. Check market depth and order size, and use an execution method appropriate to liquidity. Settlement availability and the timing of fund redemptions may differ; do not promise the same cash can be redeployed immediately in every product.
Step-by-step method
- Direct new cash toward suitable underweight allocations.
- Estimate total execution and tax cost.
- Sequence transactions around genuine cash availability.
A saver can correct modest drift through several months of contributions. The memo compares this route with an immediate sale and records the difference in cost and residual risk.
Evaluate the policy without hindsight
5.1 Risk control versus performance promises
Rebalancing can sell an asset that continues rising or buy one that falls further. Its main purpose is maintaining the intended risk profile, not ensuring the highest possible return in every market path. Evaluate whether the policy limited unwanted concentration and remained compatible with the goal. Comparing it only with the best-performing asset after the fact rewards a different and often much riskier strategy.
5.2 Records and behavioural discipline
Keep before-and-after weights, the trigger, cash-flow adjustments, estimated costs and the reason for any override. Review whether bands are practical, not merely whether the last trade made money. Repeated exceptions can reveal an unrealistic target or an undisciplined process. Improve the policy through documented experience while avoiding constant changes in response to short-term price movements.
Step-by-step method
- Record the trigger and before/after allocation.
- Review costs and deviations from policy.
- Judge success against the risk objective and spending goal.
The learner compares two teaching portfolios: one drifts toward a single winning sector; the other maintains its limits. The lesson concerns concentration control, even if the concentrated portfolio happened to earn more over that interval.
Illustrative current versus target weights
| Measure | Value |
|---|---|
| Equities now | 70 % |
| Equities target | 60 % |
| Other assets now | 30 % |
| Other assets target | 40 % |
Reference table
| Exposure | Current | Target | Adjustment |
|---|---|---|---|
| Equities | PKR 700,000 / 70% | PKR 600,000 / 60% | Reduce PKR 100,000 |
| Other assets | PKR 300,000 / 30% | PKR 400,000 / 40% | Add PKR 100,000 |
| Total | PKR 1,000,000 | PKR 1,000,000 | Zero net contribution assumed |
| Policy check | 10 percentage-point drift | Chosen teaching target | Not a personal allocation recommendation |
Glossary of key terms
- Allocation
- Distribution across underlying investment exposures.
- Drift
- Difference between current and target portfolio weights.
- Percentage point
- Arithmetic difference between two percentage weights.
- Rebalancing
- Restoring a defined allocation policy after drift or relevant change.
- Threshold
- A predefined boundary that prompts review or action.
- Turnover
- The extent to which holdings are bought and sold over a period.
Frequently asked questions
Must I rebalance every month?
No universal interval applies; choose a process suited to monitoring capacity and costs.
Should every fallen holding be topped up?
No. Recheck its suitability and investment thesis first.
Does rebalancing guarantee extra return?
No. It primarily controls exposure and concentration.
Can new savings replace selling?
Often partly, depending on the size of drift and incoming cash.
Common pitfalls
| Common mistake | A better approach |
|---|---|
| Trading without a target | Write the intended allocation first. |
| Confusing relative drift with points | Use a single defined measurement. |
| Forgetting costs | Compare correction benefits with total implementation cost. |
| Buying a broken thesis | Recheck business and product suitability. |
Your learner task
Using your own verified holdings, prepare a target/current-weight table. Calculate drift, show a contribution-first alternative, estimate implementation costs and write the conditions under which you would postpone or change the plan.
Sources & verification
Use the linked documents to check the factual and regulatory context. Source dates and limitations are stated where relevant. Educational examples and analytical frameworks are not personalised recommendations.
- PSX · Guide to investors ↗
Official investor guidance; examples and analytical frameworks in this topic are original teaching material.
- PSX · Filed company financial reports ↗
Use current issuer reports to verify company-specific inputs.
Editorial review: 22 October 2026