What happens when a SIP instalment fails

A small failure with a quiet cost

You set up a SIP, forget about it, and one month the account balance is short on the debit date. Nothing dramatic happens. No alert says "your goal is at risk". The instalment just doesn't go through, and unless you read the email or SMS you may not notice for months.

What actually happens

That month's instalment is skipped. The amount stays in your bank account; no units are bought. The fund house does not normally top it up later, so you end up with 11 instalments for the year, not 12.

Your bank may charge a fee. A failed standing instruction or mandate debit often draws a penalty, typically a few hundred rupees depending on the bank. It is a cost for a small shortfall.

The SIP usually carries on. Next month's instalment is attempted as normal. But fund houses set their own rules on repeated failures, and many cancel a SIP after a small number of consecutive misses. If yours is cancelled you must register a new one, with a fresh mandate in some cases.

Past units are untouched. What you already bought stays in your folio. The only loss is what that month's instalment would have bought.

Why debits fail

• Low balance on the debit date, often because salary credits late or another autopay runs first.
• Mandate limit too low. If you raised the SIP amount but the bank mandate caps debits below it, the larger debit bounces. This catches people after a step-up SIP raises the amount.
• Expired mandate. Mandates have an end date; a SIP running beyond it fails.
• Bank account changes. A closed account, a changed signatory or a blocked card can break the link.
• Bank holiday or technical downtime on the debit date.

How to prevent it

1. Set the SIP date just after your salary lands, not on the 1st when it may arrive on the 3rd. Does SIP date matter shows that the choice of day matters far less for returns than for reliability.
2. Keep a buffer. A balance of at least one month's SIPs and EMIs in the debit account is a simple fix. The emergency fund guide is a good place for that buffer to live.
3. Raise the mandate limit when you raise the SIP, or pick a limit with headroom at the start.
4. Track the end date. Calendar a reminder two months before the mandate or SIP expires.
5. Read the failure message. The SMS or email from your bank or fund house names the reason, and that tells you which fix to apply.

What to do after a failure

• Don't try to double up reflexively. If you can afford it, you may invest the missed amount as a one-time purchase, but nothing requires you to. A single skipped month in a multi-year SIP changes the outcome very little; a cancelled SIP you never notice changes it a lot.
• Check the status of the SIP in your fund house or platform account. See whether it is still active, and how many failures are recorded.
• Re-register if cancelled, with a mandate that has room for the amount and a sensible end date.
• Don't treat it as a signal about the market. A failed debit is a cash-flow event, not a verdict on the fund.

How much does one miss matter?

Very little, in isolation. Missing one ₹10,000 instalment out of 120 in a ten-year SIP means roughly 0.8% less money invested. What hurts is a SIP that stays silently cancelled, or the habit of skipping when markets are down, a pattern covered in should you stop your SIP in a market crash. The SIP cost-of-delay calculator shows the effect of a late start, which is the larger version of the same problem.

The takeaway

A failed SIP is cheap to fix and expensive to ignore. Put the debit date after your salary, keep a buffer, and check the status once a quarter. For the basics of how a SIP works, see the SIP guide.

This is general information; fund houses and banks set their own rules on fees and cancellations, so check the terms on your SIP registration.