Say a notice lands in your GST portal on 14 October 2026. It is titled ASMT-10, it covers FY 2024-25, and it lists three “discrepancies” with rupee figures next to each. You have 30 days to answer. ASMT-10 is not a demand. It is the officer asking you to explain differences found while scrutinising your returns, and a clean reply in Form ASMT-11 usually closes the matter.
The trouble is that most replies are written the wrong way round. People open with a covering letter and attach whatever they can find. Officers want the opposite: a reconciliation for each point, the documents behind it, and a clear statement of what you accept and what you dispute. This guide walks through that, with a worked reply.
What is an ASMT-10 notice?
ASMT-10 is issued under Section 61 of the CGST Act read with Rule 99 of the CGST Rules. When your return is picked for scrutiny, the proper officer compares it with other data and informs you of the discrepancies in ASMT-10, where possible quantifying the tax, interest and other amounts involved. You reply in ASMT-11. If the officer accepts your explanation, the proceedings close with an order in ASMT-12.
Returns are not picked at random. Under CBIC’s scrutiny procedure for FY 2019-20 onwards (Instruction No. 02/2023-GST), GSTINs are selected on risk parameters identified by DGARM, and officers can also use data from GSTN and the e-way bill portal. So the notice usually reflects a mismatch the system has already spotted between two of your own filings, or between your filings and your suppliers’.
What discrepancies usually trigger it?
The instruction does not publish a fixed list, but the same few gaps turn up in almost every notice we see in practice:
GSTR-1 vs GSTR-3B: output tax declared in GSTR-1 is higher than tax paid through GSTR-3B.
ITC in GSTR-3B vs GSTR-2A/2B: credit claimed is more than what your suppliers’ filings support.
Reverse charge: RCM credit taken without matching RCM tax paid in cash, or RCM liability on services like GTA freight or legal fees not paid at all.
E-way bills vs GSTR-1: the value of goods moved under e-way bills is higher than the supplies you reported.
Credit from cancelled or non-filing suppliers: ITC taken on invoices from GSTINs that were cancelled, or that never filed GSTR-3B.
Most of these have innocent explanations. Timing differences between months, credit notes, stock moved to your own godown, RCM credit that never appears in GSTR-2B. The job of the reply is to prove that, line by line.
How long do you have to reply, and what happens next?
Rule 99 gives you 30 days from service of the notice, or a longer period if the officer permits. There is no fixed extension in the rule, so if you need more time, ask for it in writing before the 30 days run out and keep the acknowledgement.
Instruction 02/2023 also sets timelines for the officer, which tell you what to expect:
Situation | What the officer is expected to do |
|---|---|
Reply accepted | Close the case with ASMT-12, within 30 days of your reply |
Reply not satisfactory | Move to demand proceedings (Section 73 or 74, or 74A for FY 2024-25 onwards) within 30 days of the reply, or refer the case for audit or investigation (Sections 65, 66 or 67) with the Commissioner’s approval |
No reply within 30 days | Start demand proceedings within 15 days after the 30-day period ends |
One update to read alongside the instruction. For tax periods from FY 2024-25 onwards, demand notices are issued under the new Section 74A, which replaced Sections 73 and 74 for those years. Under 74A, in a case that does not involve fraud, if you pay the tax and interest before a show cause notice is issued and inform the officer, no notice is issued and no penalty applies for that amount. That makes the ASMT-10 stage the cheapest point to settle anything that is genuinely short.
How do you reply to ASMT-10 on the GST portal?
Log in and go to Services > User Services > View Additional Notices/Orders. Open the case and download the notice from the Notices tab.
Open the Replies tab and select Notice to start an ASMT-11.
Enter your explanation and, where you accept a discrepancy, the amount admitted and paid.
Upload your reply letter, reconciliations and supporting documents.
Tick the verification, choose the authorised signatory, preview the PDF, then file with DSC or EVC.
Save the acknowledgement. The case status should show “Reply furnished, pending for order by tax officer.”
If you are admitting any tax, pay it through Form DRC-03 before you file, and quote the DRC-03 reference in the reply. A reply that says “we accept and will pay” without a payment reference rarely gets an ASMT-12.
A worked example: one notice, three discrepancies
Say you run a tiles dealership in Rajkot. Your ASMT-10 for FY 2024-25 lists three points. Here is how your accountant reconciles them.
Point 1: output tax in GSTR-1 exceeds GSTR-3B by ₹48,000
Matching the two returns month by month shows two causes. A March 2025 invoice carrying ₹36,000 of tax was reported in March’s GSTR-1, but the tax was paid through April’s GSTR-3B, filed on 20 May 2025. That is a timing difference, but it was 30 days late, so interest is due: ₹36,000 × 18% × 30 ÷ 365 = ₹533.
The remaining ₹12,000 is a genuine miss. An October 2024 invoice was left out of that month’s GSTR-3B and never caught. You accept it. If you pay on 5 November 2026, interest runs for 715 days from the 20 November 2024 due date: ₹12,000 × 18% × 715 ÷ 365 = ₹4,231.
Point 2: ITC in GSTR-3B exceeds GSTR-2B by ₹82,000
₹54,000 is credit on reverse charge paid in cash on GTA freight. RCM credit on supplies from unregistered transporters does not appear in GSTR-2B at all, so you attach the RCM tax payment entries from GSTR-3B and the freight bills. The other ₹28,000 is from a supplier who filed the March 2025 invoice late; it shows up in your May 2025 GSTR-2B. You attach that GSTR-2B extract and the purchase invoice.
Point 3: e-way bill value exceeds GSTR-1 by ₹5,60,000
The difference is stock moved from your shop to your own godown in the same city under the same GSTIN. That is not a supply. You attach the delivery challans and the e-way bills, which show your own GSTIN as both consignor and consignee.
What the reply admits
Discrepancy | Amount in notice | Explained | Admitted and paid |
|---|---|---|---|
Output tax, GSTR-1 vs GSTR-3B | ₹48,000 | ₹36,000 | ₹12,000 tax + ₹4,231 interest + ₹533 interest on late payment |
ITC, GSTR-3B vs GSTR-2B | ₹82,000 | ₹82,000 | Nil |
E-way bill vs GSTR-1 (value) | ₹5,60,000 | ₹5,60,000 | Nil |
Total paid through DRC-03 before filing: ₹12,000 + ₹4,231 + ₹533 = ₹16,764. The tax goes under CGST and SGST in equal halves, since the October invoice was an intra-state sale.
How should the ASMT-11 reply letter be structured?
Keep it short and numbered to match the notice. A structure that works:
Reference line: GSTIN, notice reference number, date of notice, tax period.
One paragraph per discrepancy, in the same order as the notice: the figure in the notice, your reconciled figure, the reason for the difference, and the annexure number that proves it.
Admitted amounts: tax and interest admitted, with the DRC-03 ARN and date.
Closing request: that the proceedings be dropped by issuing ASMT-12.
Each annexure should be a reconciliation, not a data dump. A month-wise table of GSTR-1 against GSTR-3B is easier for an officer to accept than 200 pages of invoices.
What mistakes make an ASMT-10 reply fail?
Disputing everything. If part of the gap is real, say so and pay it. A reply that admits ₹12,000 and documents the rest reads as credible. One that denies all of it invites an audit.
Explanations without numbers. “Difference due to timing” is not an explanation until you show which invoice, which month and which return.
Paying without interest. Tax paid late carries interest even if the difference was only timing. Leave it out and the point stays open.
Missing the deadline. After 30 days the officer can proceed without hearing from you, and your silence goes into the file.
Books that do not match the returns. If your purchase register disagrees with both GSTR-3B and GSTR-2B, the reconciliation cannot be built. Fix the books first.
Where hisabkitab fits in
Most of the effort in an ASMT-10 reply goes into the reconciliations, and they are much easier when the books were reconciled every month in the first place. hisabkitab’s GST module reconciles GSTR-2B against your purchase register with AI, gives you ITC and liability reports, and flags wrong GSTINs and duplicate invoices before you file. The same habit makes your monthly IMS review quicker, and we have written about catching GST errors before they turn into notices.
When a notice does arrive, the month-wise sales, purchase, GST and e-way bill reports give you the annexures, and the audit trail shows who changed which entry and when. CAs replying for several clients can do this from one login with the CA module.
Frequently asked questions
Is ASMT-10 a show cause notice?
No. ASMT-10 asks you to explain discrepancies found in scrutiny. A show cause notice comes later, and only if your reply is not accepted or you do not reply.
What is the time limit to reply to ASMT-10?
30 days from the date the notice is served, or a longer period if the officer allows it. Ask for any extension in writing before the deadline.
Can I pay part of the amount and dispute the rest?
Yes. Rule 99 allows you to accept a discrepancy and pay the tax and interest. Pay the admitted part through DRC-03, quote it in ASMT-11, and explain the rest with reconciliations.
What happens if I ignore an ASMT-10 notice?
The officer can start demand proceedings after the 30-day period, under Section 73 or 74 for periods up to FY 2023-24 and Section 74A from FY 2024-25. The demand can then carry interest and penalty on top of the tax.
Do I need a CA to reply to ASMT-10?
The law does not require one, and a simple timing difference can be explained by the business itself. Where the gap involves ITC eligibility, RCM or large amounts, a CA’s review of the reconciliation is usually worth it.
What is ASMT-12?
ASMT-12 is the order the officer issues when your reply is accepted. It closes the scrutiny for that period, so keep a copy with your GST records.
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