It is an instruction, not an asset
A systematic investment plan is a standing instruction: on this date each month, take this amount from this bank account and buy units of this scheme at that day's NAV.
That is the entire mechanism. There is no SIP product, no SIP account, and no SIP asset class. You are not invested in a SIP — you are invested in a mutual fund, and the SIP is the method by which you keep buying it.
Three loose phrases follow from getting this wrong, and all three are worth retiring. “SIP returns” — there are none; there are the fund's returns, experienced across many entry dates. “Investing in a SIP” — you invest in a scheme. “Which SIP should I buy?” — the question is which scheme, and the SIP is how you pay for it.
This is not pedantry. Someone who believes they hold a SIP will compare SIPs; someone who knows they hold an equity fund will compare equity funds, which is the comparison that decides the outcome.
What happens each month
Four steps, and one of them surprises people.
- The mandate fires. A bank mandate you registered once authorises the debit. Registration takes some days to activate, which is why a first instalment often starts a cycle later than expected.
- The money moves and must actually reach the fund.
- Units are allotted at the applicable NAV — the day's NAV if the cut-off and realisation conditions were met, otherwise the next business day's. This is the step people miss: your chosen SIP date is not a guarantee of that date's NAV.
- The units land in your folio, and each instalment carries its own purchase date, which matters for exit load and for holding period.
That last point has a practical consequence worth holding on to: a SIP does not create one holding. It creates a stack of separate purchases, each with its own age. Redeeming “the SIP” means redeeming units that were bought on many different dates.
A SIP does not make a fund safer
This is the misconception with the largest gap between how common it is and how much it costs.
A SIP into an equity fund is an investment in an equity fund. If that fund falls 40%, a SIP investor's accumulated units fall 40% too. The instruction changes when you bought, not what you own, and no schedule of purchases converts equity risk into something milder.
What a SIP genuinely does is narrower and still valuable: it removes the risk of putting everything in on one unlucky day. That is entry-timing risk, which is a real risk and a small one next to market risk. Conflating the two is how people end up with an equity SIP funding an expense eighteen months away.
| A SIP changes… | A SIP does not change… |
|---|---|
| When you buy — many dates instead of one | What you own — the scheme and its risk |
| Your average cost per unit | How far the fund can fall |
| Exposure to one unlucky entry date | The horizon the fund is suitable for |
| Whether investing depends on you remembering | Whether equity is the right asset for the goal |
The horizon question is decided by the fund, not by the method of buying it.
What rupee-cost averaging does
A fixed rupee amount buys more units when NAV is low and fewer when it is high, so your average cost per unit lands below the average NAV over the period. That is real, and it is arithmetic rather than a claim.
What it is not is a return-generating mechanism. In a market that mostly rises, staggering entry means most of your money was invested for less time and a lumpsum would have finished ahead — not because averaging failed, but because time in the market did the work. In a market that falls and then recovers, the SIP accumulates units cheaply and comes out ahead.
So the comparison is a question about the path the market took, which nobody knows in advance. Averaging reduces the consequence of bad timing. It does not create return — worked through in SIP or lumpsum?
Stopping, pausing and the crash problem
The instruction can be stopped at any time, and the units already bought stay invested. There is no penalty for stopping and no obligation to complete any number of instalments.
The mechanical point that matters: stopping a SIP during a fall removes precisely the instalments that buy the most units. The whole averaging effect is concentrated in the months when NAV is low, and those are exactly the months in which stopping feels most sensible.
Whether that matters to the final outcome depends on whether the market recovers, which nobody knows in advance. But the effect is mechanical and worth seeing clearly before the decision arrives, rather than during it.
If cashflow is the reason, most fund houses allow a pause for a limited number of instalments, which keeps the mandate alive. That is a different decision from stopping, and it is usually the one people actually want.
Step-up SIPs, and why the default is a slow leak
A fixed ₹10,000 monthly SIP started today is a smaller commitment every year, in real terms and relative to a rising income. Left alone for a decade it quietly becomes a minor line item.
A step-up (or top-up) SIP raises the instalment on a schedule you set — a fixed percentage or a fixed amount each year. The mechanism is uninteresting; the effect is not, because the increases apply early enough to compound for most of the horizon.
The honest framing is that a step-up is not a cleverer strategy. It is the same strategy with the contribution kept in step with your income, and the alternative is a contribution that shrinks by default.
How to measure what it did
Because instalments land on many dates, a SIP's return cannot be computed the way a lumpsum's is. Dividing the gain by total invested treats every rupee as though it went in on day one, which understates the result; annualising that by dividing by years compounds the error.
The correct measure is XIRR — the annual rate that reconciles every instalment on its actual date with today's value. Set out in full in XIRR, CAGR, and which one your return actually is.
And because a SIP accumulates a new entry date every month, the fund's rolling-return distribution is a far more relevant lens than any single trailing figure.
Testing a SIP before committing to it
A SIP is a decade-long commitment made on a five-minute decision, which is an argument for simulating it first.
FNOTrader's Mutual Funds app runs any contribution schedule against a scheme's real NAV history — around 34 million NAV rows, refreshed nightly at 22:30 IST — and reports XIRR, invested against value, and the maximum drawdown along the way. The drawdown figure is the one worth looking at hardest: it is the number that decides whether you would have kept going.
Formulas are published in the user guide, no login required.
Common questions
What is a SIP in mutual funds?
A standing instruction to invest a fixed amount in one scheme on one date each month, bought at that day's applicable NAV. It is a method of buying a fund, not a product or an asset class in its own right.
Is a SIP safer than a lumpsum?
It removes entry-timing risk — the risk of putting everything in on one unlucky day — but not market risk. A SIP into an equity fund is an investment in an equity fund, and if that fund falls 40% the accumulated units fall with it.
Do I get the NAV of my chosen SIP date?
Not necessarily. Units are allotted at the applicable NAV, which depends on the cut-off time and, for most schemes, on the money having actually reached the fund. If either condition is missed the next business day's NAV applies.
What happens if I stop my SIP?
The instruction ends and no further instalments are debited, but the units already bought remain invested. There is no penalty and no minimum number of instalments — though most fund houses also allow a temporary pause, which is usually what someone with a cashflow problem actually wants.
Why is stopping a SIP during a market fall costly?
Because a fixed rupee amount buys the most units when NAV is lowest, so the instalments skipped during a fall are exactly the ones the averaging effect depends on. Whether it changes the final outcome depends on whether the market recovers, but the mechanical effect is certain.
What is a step-up SIP?
A SIP whose instalment rises on a set schedule, usually a fixed percentage or amount each year. It keeps the contribution in step with a rising income — the alternative being a fixed instalment that becomes a smaller commitment every year by default.
How do I calculate my SIP return?
With XIRR, which reconciles every instalment on its actual date against the current value. Dividing total gain by total invested treats every rupee as though it went in on day one and understates the return.
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