Why Your Carefully Planned Portfolio Drifts Out of Shape
You decided on a 70% equity, 30% debt split — a standard allocation for someone in their 30s. Three years of strong equity returns later, your portfolio is 85% equity and 15% debt. You didn't change anything. The market did.
This drift isn't harmless. An 85/15 portfolio has 40% more downside than a 70/30 in a market crash. You took on more risk than you planned, without making a conscious decision. Rebalancing is how you correct that drift back to your intended risk level — selling some of what went up and buying some of what lagged. It's "sell high, buy low" codified into a rule.
The catch in India: rebalancing is taxed. Every equity unit sold attracts LTCG or STCG. Every debt unit sold faces slab-rate taxation. Done poorly, rebalancing's tax drag erases the risk-management benefit. This guide shows how to rebalance effectively without letting the tax office win.
The Drift Problem in Numbers
Assume you start with ₹10 lakh in a 70/30 portfolio:
| Year | Equity Value (12% return) | Debt Value (7% return) | Total | Equity % |
|---|---|---|---|---|
| Start | ₹7.00 lakh | ₹3.00 lakh | ₹10.00 lakh | 70.0% |
| Year 1 | ₹7.84 lakh | ₹3.21 lakh | ₹11.05 lakh | 70.9% |
| Year 3 | ₹9.83 lakh | ₹3.68 lakh | ₹13.51 lakh | 72.8% |
| Year 5 | ₹12.34 lakh | ₹4.21 lakh | ₹16.54 lakh | 74.6% |
| Year 10 | ₹21.74 lakh | ₹5.90 lakh | ₹27.64 lakh | 78.6% |
Even with "normal" returns, the equity allocation drifts 8 percentage points over 10 years. Add a bull market (18–20% equity returns for 3 years) and you can easily drift 15–20 percentage points without noticing.
The Two Main Rebalancing Methods
1. Calendar Rebalancing
Rebalance on a fixed date every year — most commonly 31 March (end of financial year) or 31 December (calendar year-end). Simple, disciplined, easy to remember. Drawback: you rebalance even when drift is minimal, wasting transaction friction.
2. Threshold Rebalancing
Rebalance only when any asset class drifts more than a set percentage from its target. Common thresholds: 5% absolute (70/30 becomes 75/25 or 65/35) or 20% relative (70% target drifts to 84% or 56%). Drawback: requires active monitoring.
The Hybrid That Actually Works
Most rigorous studies (including Vanguard's long-term research) find a "Calendar + Threshold" approach wins: check once a year, rebalance only if drift exceeds the threshold. You get discipline without over-trading. For a typical 70/30 portfolio, a 5-percentage-point threshold checked annually on 31 March is a solid default.
The Tax-Efficient Way: Rebalance Through New Contributions
This is the single most important rebalancing technique most articles miss. Instead of selling equity units to bring the allocation back in line, direct your ongoing SIPs and lumpsum additions disproportionately to the underweight asset class.
Example: your portfolio is 78% equity, 22% debt instead of the target 70/30. You're investing ₹50,000/month via SIP. Rather than selling ₹3 lakh of equity (triggering LTCG tax), redirect your next 6 months of SIPs 100% into debt. Over those 6 months, the debt allocation catches up — and you've paid zero tax on the rebalancing.
This approach works beautifully in accumulation phase (when you're still adding money). It fails only in two situations: (1) the drift is so large that new contributions can't absorb it within a reasonable time, and (2) you're in the de-accumulation phase (retirement), where there are no new contributions to redirect.
The Tax Cost of Rebalancing by Selling
When new contributions can't correct the drift fast enough, you'll need to sell. Here's the tax impact to keep in mind:
- Equity mutual funds held 12+ months: LTCG at 12.5% on gains above ₹1.25 lakh per year. Use the ₹1.25 lakh exemption every year by staggering sales.
- Equity mutual funds held under 12 months: STCG at 20% — almost always worth waiting 12 months to avoid this.
- Debt mutual funds: Slab rate on the full gain, regardless of holding period (post-April 2023 rules).
- PPF, EPF, SSY, tax-free bonds: No tax on withdrawal — but you typically can't withdraw these easily anyway.
- Stocks held 12+ months: Same as equity MFs — 12.5% LTCG above ₹1.25 lakh/year.
The golden rule: prefer tax-exempt or tax-neutral sources for rebalancing. Sell from equity taxable accounts only when nothing else is available.
A Worked Example: Rebalancing a ₹30 Lakh Portfolio
You have ₹30 lakh total: ₹24 lakh equity, ₹6 lakh debt (80/20 — drifted from target 70/30). To rebalance, you need to reduce equity by ₹3 lakh and add ₹3 lakh to debt.
| Approach | Method | Tax Cost (assumed 30% bracket) |
|---|---|---|
| A. Sell ₹3 lakh of equity in one shot | Lumpsum redemption | ~₹22,000–25,000 (LTCG 12.5% on ~₹1.8 lakh of gains above exemption) |
| B. Redirect next 12 months of SIP into debt | New-contribution rebalancing | ₹0 (no sale) |
| C. Sell ₹1.25 lakh of equity this year, ₹1.75 lakh next year | Staggered LTCG harvesting | ~₹6,000–8,000 (uses exemption twice) |
Option B is free. Option C splits the tax load. Option A is the lazy default — and the most expensive.
When You Should NOT Rebalance
- Drift is under your threshold (say under 5%). Minor deviation doesn't meaningfully change portfolio risk.
- You're within 1 year of your goal. Don't rebalance into more risk just because the target says you should — capital preservation dominates here.
- You'd trigger a large STCG hit. If recent purchases would be sold within 12 months, wait.
- The rebalancing is behavioural, not drift-driven. Selling equity because "markets feel high" isn't rebalancing — it's timing, and it almost always loses.
- You're already in a hybrid, balanced advantage, or multi-asset fund. These rebalance internally — you'd be rebalancing a rebalancer.
Common Rebalancing Mistakes
- Rebalancing too often. Quarterly rebalancing produces more tax cost than risk benefit for most portfolios. Annual is sufficient.
- Rebalancing based on "feelings" about the market. Selling after a 20% rally because it "has to come down" is market timing, not rebalancing. Rebalancing is triggered by allocation drift, not by market levels.
- Ignoring rebalancing entirely. The other common mistake. An undisciplined 10-year portfolio can drift so far that a single crash wipes out years of gains.
- Rebalancing purely within equity. If your equity is 30% small-cap, 20% mid-cap, 50% large-cap — rebalancing within equity matters. A drift to 50% small-cap dramatically changes the portfolio's risk profile.
- Selling gains, holding losses. Behavioural bias — most investors sell what went up and hold what went down. Rebalancing is the opposite: trim winners, top up laggards.
- Rebalancing on the last day of FY without planning. You end up with a 31 March sale that triggers LTCG in that FY with no offsetting capital losses planned.
Frequently Asked Questions
How often should I rebalance?
For most investors, once a year is plenty. Check your portfolio around 15 March (early enough to plan FY-end moves), and rebalance only if drift exceeds your threshold (typically 5%).
Should I rebalance in a falling market?
Absolutely — and this is when rebalancing creates the most value. In a market crash, your equity allocation shrinks below target. Rebalancing means buying more equity at lower prices. It feels scary, but it's the entire point of mechanical rebalancing.
Does rebalancing improve returns?
Not always — and that's not its job. Rebalancing controls risk, not returns. In long bull markets, a no-rebalance portfolio sometimes beats a rebalanced one (because equity keeps rising). Rebalancing pays off during downturns by ensuring your risk stays within what you can actually tolerate.
Can I rebalance just by switching between schemes within the same AMC?
Yes, but SEBI treats inter-scheme switches as a redemption + fresh purchase for tax purposes — same tax impact as selling and buying across AMCs. No shortcut on tax.
How do I rebalance if most of my equity is in ELSS (under 3-year lock-in)?
You cannot sell ELSS units within lock-in. Rebalance by redirecting new contributions toward debt, or use NPS/EPF contributions to naturally increase your debt allocation without selling anything.
Should I rebalance my EPF/PPF/NPS separately or consider them part of the total portfolio?
Think holistically. EPF and PPF count as your "debt" allocation. If they're already 25% of your net worth, you may need less additional debt than you thought. Rebalance based on your total financial picture, not fund-by-fund.
Is there an easy way to see my current allocation without doing manual math?
Yes — aggregation platforms like CAMS, KFintech's MF Central, or apps like INDmoney, Kuvera, and MF Utilities show real-time asset allocation across all your holdings. Check at least once a quarter, even if you rebalance only annually.
The Final Word
Rebalancing is the quietest form of risk management in investing — almost mechanical, emotionally uncomfortable, and disproportionately valuable. The mistake most Indian investors make isn't how they rebalance, but that they never do. Set a calendar reminder for 15 March every year. Check your allocation. If drift exceeds 5 percentage points, redirect your SIPs or stagger sales across financial years. Done consistently, this single habit protects years of compounding from a single bad market year.