Portfolio rebalancing: when and why you must sell winning assets

Rebalancing asks you to sell the thing that has been working and buy the thing that has not. Every instinct you have will object, which is exactly why it needs to be a rule rather than a decision.

Asset allocation covers what the split should be. This is about actually holding it.

Why drift is a risk decision you never made

Set 60% equity and 40% debt, then do nothing. After a strong equity run it is 75/25.

Nobody chose that. Your portfolio is now materially riskier than the one you signed up for, and the change happened silently — which means you will discover it in the next drawdown, when 75% equity behaves like 75% equity.

Rebalancing is not primarily a return strategy. It is risk control, and any return benefit is a side effect of systematically trimming what has run and adding to what has not.

Two triggers, and the sensible combination

Calendar — check on a fixed date each year. Simple, and enough for most people.

Threshold (bands) — act only when an asset class drifts beyond a set band from target, commonly ±5 percentage points. This ignores noise and forces action when it matters.

The practical version used by most disciplined investors: check annually, act only if something is outside its band. Checking more often does not improve outcomes and does increase cost — which, in India, mostly means tax.

Fix the date and the bands in advance, in writing. The whole point is removing judgement from the moment.

The execution ladder, cheapest first

Rebalancing in a taxable account costs money. Work down this list:

1. Rebalance with new money. Direct your SIPs and any lump sum into the under-weight asset instead of selling the over-weight one. Zero tax, zero exit load. For anyone still accumulating, this alone does most of the work and should be the default.

2. Use the annual exemption deliberately. ₹1,25,000 of long-term equity gain per financial year is exempt. Realising up to that limit costs nothing.

3. Rebalance inside a tax-sheltered or internally-rebalanced wrapper. A balanced advantage or multi-asset fund rebalances internally, and that is not a taxable event for you.

4. Only then sell. And when you do, check the holding period — units under a year attract 20% short-term rather than 12.5%, and units are matched oldest first, which usually works in your favour.

The costs, stated plainly

• Equity sold under 12 months: 20%.
• Equity sold at 12 months or more: 12.5%, above the ₹1,25,000 exemption.
• Most debt funds: slab rate, any holding period.
• Plus exit load on young units.

So a mechanical annual rebalance can hand back a real slice of the gain it just locked in. Widening the bands from ±5 to ±7 or ±10 is a legitimate response if each trip is expensive.

What is not a legitimate response is skipping rebalancing entirely. Paying 12.5% on a gain is a smaller problem than carrying 85% equity into a bear market you had planned for at 60%.

The psychological part

The reason people do not rebalance is not tax. It is that in the moment, the correct action always feels wrong:

• After a bull run you sell equity — and it keeps rising for another year, and you feel foolish.
• After a crash you buy equity — into the asset everyone is fleeing, with the news telling you it will fall further.

That discomfort is the mechanism. If it felt comfortable, everyone would do it and there would be nothing to harvest. Pre-committing to bands is how you make the decision at a moment when you are capable of making it, rather than at the moment you must act. See the psychology of a market crash.

Pitfalls to avoid

• Rebalancing too often. Quarterly is usually cost without benefit.
• Rebalancing on a market view. “I will wait for it to come back” is timing, not rebalancing.
• Ignoring the tax cost entirely. Use inflows and the exemption first.
• Rebalancing between funds in the same asset class. Swapping one large-cap fund for another is not rebalancing; it is churn.
• Only rebalancing downward. Selling equity after a run but never buying it after a crash is a ratchet, and it is the more expensive half to skip.

Key takeaway

Rebalancing keeps your risk where you put it, and its value is control rather than return. Pick a date and a band in advance, check once a year, and execute with new money before you execute with a sale. The moment it feels wrong is the moment it is working — which is precisely why it has to be a rule you wrote down when you were calm.