You just got a bonus. Or sold a property. Or finally cashed out an FD. You have a meaningful lump sum and the question is: dump it all into mutual funds now, or stagger it over a year as a "SIP"?
This article gives you the answer with numbers, not opinions.
The math, in two lines
In a rising market, lumpsum wins. Your money is invested longer, compounds more.
In a flat or declining market, SIP wins. You buy more units when prices are low, fewer when they're high — rupee-cost averaging.
Historically, equity markets rise ~70% of the years. So lumpsum wins ~70% of the time.
Run the actual numbers
Scenario A: rising market, 15% return
- Lumpsum ₹12L at the start, 1 year later at 15% = ₹13.80L
- SIP ₹1L per month for 12 months (15% annualized = ~1.17%/month), end value ≈ ₹12.96L
- Lumpsum wins by ~₹84k.
Scenario B: V-shaped market, falls 20% mid-year, recovers to start
- Lumpsum ₹12L → falls to ₹9.6L → recovers to ₹12L (flat)
- SIP buys some units at the low; final value ≈ ₹12.7L
- SIP wins by ~₹70k.
Scenario C: declining market, −10% over the year
- Lumpsum ₹12L → ₹10.8L
- SIP averages down, ends ≈ ₹11.3L
- SIP wins by ~₹50k.
So which one is more likely? Indian equities over the past 25 years have produced a positive nominal return in roughly 70% of calendar years. That's the percentage of years lumpsum wins.
But results-on-average isn't the right framing
The right framing is regret-adjusted return. If you put ₹12L in at one shot and the market drops 20% the next quarter, you'll be miserable. If you SIP and the market drops, you're happier (buying at the dip) — and you stay invested.
For most retail investors, the SIP wins the behavior war even when it loses the math war. Quitting at the bottom is the single largest cost in equity investing, and SIPs reduce the temptation.
The practical recommendation
| Situation | What to do |
|---|---|
| Bonus / windfall, no debt, comfortable with risk | Lumpsum into equity mutual funds |
| Same situation but new to investing | STP (Systematic Transfer Plan) over 6–12 months |
| Volatile career income (consultants, founders) | SIP with cash buffer in liquid fund |
| Approaching retirement (< 5 years) | STP spread over 18+ months into debt-heavy funds |
STP — systematic transfer plan — is the underrated middle ground. Park your lump sum in a liquid fund (earns 6–7%) and transfer ₹1L/month into an equity fund. You get SIP discipline with productive cash parking.
When the answer is "neither"
If you have outstanding debt above 8% (credit cards, personal loans), the math says pay that off first. A guaranteed ~12–18% saving (interest avoided, post-tax) beats any equity SIP expected return.
Use the SIP calculator, the lumpsum calculator, or — when it's built — the prepayment toggle on the EMI calculator.
