Chapter 5 of 15
What is SIP and How Does it Work?
Rupee cost averaging, compounding, step-up SIP, and common mistakes.
A SIP is a method of investing a fixed amount in a mutual fund at regular intervals (usually monthly), automatically deducted from your bank account.
Suvash sat at his desk on the 2nd of every month and did the same calculation.
₹75,000 salary comes in. ₹20,000 goes home to Odisha: Amma's medicines, younger sister's college fees, father's phone bill. ₹15,000 disappears into Bengaluru rent and food. Then there's the random ₹3,000–5,000 that just... evaporates. Chai, auto rides, the occasional movie with office friends.
What's left? Usually ₹8,000. Sometimes ₹12,000. Never predictable.
One evening, his colleague Priya mentioned she had a SIP running since 2021. "I don't even feel it," she said. "It just goes. But the portfolio keeps growing."
Suvash had one question: "How does ₹5,000 a month actually become something real?"
What Exactly Is a SIP?
On the 5th of every month, ₹5,000 leaves Suvash's bank account automatically. It goes into a mutual fund. The fund buys him some units at whatever NAV it's trading at that day. Next month, same thing. And the month after. For years.
That's a SIP.
No timing the market. No remembering to invest. No discipline required beyond the first setup. The money moves before Suvash can spend it on something else.
Suvash gets paid on the 1st. He set his SIP for the 5th. By then the money is in his account, and the auto-debit picks it up cleanly. If you set it too close to salary credit, the mandate might fail on weekends or processing delays.
The Magic Mechanism: Rupee Cost Averaging
Here's where it gets genuinely interesting.
The market goes up. The market goes down. Normal people try to "time" it: buy low, sell high. They almost always fail. They buy when the market is exciting (high), and they panic-sell when it's scary (low). Classic buy-high-sell-low disaster.
SIP solves this automatically. Because you invest the same amount every month, you buy more units when the market is low and fewer units when the market is high. Over time, your average cost per unit becomes lower than the average NAV. This is called rupee cost averaging.
Suvash invests ₹5,000 every month in a Nifty 50 index fund. Here's what happens:
Month 1: NAV = ₹100 → Suvash gets 50 units Month 2: Market dips. NAV = ₹80 → Suvash gets 62.5 units Month 3: Market dips more. NAV = ₹70 → Suvash gets 71.4 units Month 4: Recovery begins. NAV = ₹85 → Suvash gets 58.8 units Month 5: More recovery. NAV = ₹95 → Suvash gets 52.6 units Month 6: Back up. NAV = ₹100 → Suvash gets 50 units
Total invested: ₹30,000 Total units: 50 + 62.5 + 71.4 + 58.8 + 52.6 + 50 = 345.3 units Current value at ₹100 NAV: 345.3 × ₹100 = ₹34,530
Average NAV over 6 months was ₹88.3. Suvash's average buy price? Only ₹86.9 per unit. He automatically bought cheaper.
This is why SIP investors who keep investing through market crashes often come out ahead. The crash is actually doing them a favor. They're buying more units at low prices.
The entire benefit of rupee cost averaging disappears if you pause or cancel your SIP when markets fall. That's when you're buying the most units at the cheapest price. Stopping then is like stopping a discount shopping spree because prices are lower.
SIP vs Lump Sum: What's Actually Better?
| Factor | SIP | Lump Sum |
|---|---|---|
| Best for | Regular salaried investors | Those with a windfall/bonus |
| Market timing risk | Eliminated by averaging | High: timing matters a lot |
| Discipline required | Low (automated) | High (must resist spending) |
| Returns in rising market | Slightly lower (averaging up) | Better (all money invested early) |
| Returns in volatile market | Usually better | Can be much worse |
| Minimum amount | ₹500/month | ₹1,000 typically |
For Suvash, SIP is the obvious choice. He doesn't have ₹1 lakh sitting around to invest all at once. He has ₹5,000–8,000 free per month. SIP is built exactly for him.
How to Actually Set Up a SIP
Setting up a SIP takes about 20 minutes if you have your PAN card, Aadhaar, and bank details ready.
Step 1: Complete KYC This is a one-time process. You can do it online through most platforms. You'll need PAN + Aadhaar OTP verification. Once done, it's valid for all mutual funds across all AMCs.
Step 2: Choose a Platform
- Groww, Paytm Money, Kuvera, Zerodha Coin: direct plan apps (no commission)
- Bank portals (SBI, HDFC etc.): usually regular plans (slightly higher fees)
- AMC websites directly: also direct plans
Suvash chose Kuvera because it shows direct plans only and has a clean portfolio tracker.
Step 3: Choose Your Fund For a beginner like Suvash, a Nifty 50 or Nifty Next 50 index fund is a sensible starting point. Low cost, broad diversification, no manager risk.
Step 4: Set the Amount and Date ₹5,000/month. Date: 5th of every month. He set up a mandate (bank auto-debit permission), a one-time process.
Step 5: Done. Now Don't Touch It. This is genuinely the hardest step.
How Much Should Suvash Actually Invest?
Suvash has ₹8,000–12,000 free per month after all expenses and remittances. Here's a sensible split:
| Bucket | Amount | Purpose |
|---|---|---|
| Emergency fund (first) | ₹3,000/month until ₹50,000 built | Liquid fund or savings account |
| ELSS SIP | ₹2,000/month | Tax saving under 80C |
| Equity SIP (index fund) | ₹3,000/month | Long-term wealth building |
| Buffer | ₹0–4,000 | Absorb family emergencies |
Once the emergency fund is built, all ₹5,000 can go into the equity SIP.
What Happens to a SIP Over Time?
Here's the honest math. Suvash invests ₹5,000/month for 20 years at a 12% CAGR (Nifty 50 historical average):
- Total invested: ₹5,000 × 240 months = ₹12,00,000
- Expected corpus: ~₹49,95,000 (roughly ₹50 lakhs)
- Gains from compounding: ₹37,95,000
He puts in ₹12 lakhs. He gets back ₹50 lakhs. The difference is compounding: returns on returns on returns.
Suvash gets a 10% raise next year. Instead of spending the extra ₹7,500/month, he increases his SIP by 10% too, from ₹5,000 to ₹5,500. If he does this every year, his ₹50L corpus becomes closer to ₹90L over the same 20 years. This is called a step-up SIP and most platforms support it.
Common SIP Mistakes Suvash Nearly Made
"I'll start next month when I have more money." This is a lie Suvash told himself for 8 months. There's never a perfect time. ₹500/month started today beats ₹5,000/month started next year.
"The market is high right now. I'll wait." This is trying to time the market. Nobody can do this consistently. Start now. The SIP mechanism handles the market volatility for you.
"I paused my SIP for 3 months during my family emergency." Understandable. But those 3 months happened to be when the market was cheapest (COVID crash, election results dip, etc.). That's the downside of pausing. You miss the bargain buys.
"I'm investing in a 'trending' fund my colleague told me about." Past performance is not future performance. A fund that did 35% last year often underperforms in the next 3 years. Stick to a boring index fund and don't chase returns.
Key Takeaways
- A SIP automatically invests a fixed amount monthly, perfect for salaried investors like Suvash
- Rupee cost averaging means you buy more units when markets are down. This is a feature, not a bug
- Set your SIP date 3–5 days after your salary credit date
- Never pause a SIP during a market crash. That's exactly when it's working hardest for you
- A step-up SIP (increasing by 10% annually) dramatically accelerates wealth building
- ₹5,000/month for 20 years at 12% CAGR = ~₹50 lakhs. Start today, not next month.
Ready to calculate exactly how much your SIP will grow?
Want to know which type of fund to put your SIP into?
Suvash invests ₹5,000/month. In Month 1 NAV is ₹100. In Month 2 NAV drops to ₹80. What happens to his Month 2 units?
Disclaimer: This article is for educational purposes only and does not constitute personalized financial advice. Investments are subject to market risks. Past performance does not guarantee future returns. Please consult a SEBI-registered investment adviser before making investment decisions.