Rules 99 explained: this guide covers what it means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.
Rules 99, 100 and 102 of the Central Goods and Services Tax Rules, 2017 give the forms and steps for three provisions of the Act: scrutiny of returns (section 61), assessment of non-filers and unregistered persons and summary assessment (sections 62, 63 and 64), and special audit (section 66). Rule 101, on audit, sits between them and has its own post.
This article follows the CGST Rules, 2017 as amended up to 31 October 2025 in the compilation consulted; notifications issued after that date should be checked.
Rule 99: on scrutiny of a return, the proper officer issues FORM GST ASMT-10 seeking an explanation within a time not exceeding thirty days (or such further period as he permits); the registered person replies in FORM GST ASMT-11; the officer closes in FORM GST ASMT-12. Rule 100: the orders and notices in FORM GST ASMT-13 to ASMT-18, with fifteen days to reply to the notice in rule 100(2). Rule 102: a special audit direction in FORM GST ADT-03 and the findings in FORM GST ADT-04.
The sections behind the rules
Rule 99 carries out section 61: see section 61: scrutiny and the thirty-day reply and section 61 scrutiny limits. Rule 100 serves sections 62, 63 and 64: see sections 63 and 64: unregistered persons and summary assessment. Rule 102 serves section 66: see section 66: special audit. Section 62 is headed "Assessment of non-filers of returns". For a scrutiny notice that needs a considered reply, our GST notices and litigation service can prepare it. Rule 101 on audit is in rule 101: how a GST audit is conducted.
Rule 99: scrutiny of returns
- Sub-rule (1). Where a return furnished by a registered person is selected for scrutiny, the proper officer scrutinizes it in accordance with section 61 "with reference to the information available with him". In case of any discrepancy, he issues a notice in FORM GST ASMT-10, informing the person of the discrepancy and seeking his explanation "within such time, not exceeding thirty days from the date of service of the notice or such further period as may be permitted by him", and also, where possible, quantifying the amount of tax, interest and any other amount payable in relation to the discrepancy.
- Sub-rule (2). The registered person may accept the discrepancy, pay the tax, interest and any other amount arising from it, and inform the proper officer, or furnish an explanation for the discrepancy, in FORM GST ASMT-11.
- Sub-rule (3). Where the explanation or the information submitted is found acceptable, the proper officer informs him accordingly in FORM GST ASMT-12.
Rule 100: assessment in certain cases
Rule 100 is printed as a substituted rule; the footnote records Notification No. 16/2019-Central Tax dated 29.03.2019, with effect from 01.04.2019. Rule 100(2) describes the assessment proposed under section 63 as one made on the proper officer's own judgment; the Act uses a different heading for these assessments, so read sections 62 and 63 for the exact words.
| Sub-rule | Section | What the rule requires |
|---|---|---|
| (1) | 62(1) | The order of assessment issued in FORM GST ASMT-13; a summary uploaded electronically in FORM GST DRC-07 |
| (2) | 63 | The proper officer issues a notice to a taxable person in FORM GST ASMT-14 containing the grounds on which the assessment is proposed to be made on the basis of his own judgment, and serves a summary electronically in FORM GST DRC-01; after allowing fifteen days to the person to furnish his reply, if any, he passes an order in FORM GST ASMT-15, with a summary uploaded in FORM GST DRC-07 |
| (3) | 64(1) | The order of assessment issued in FORM GST ASMT-16; a summary of the order uploaded in FORM GST DRC-07 |
| (4) | 64(2) | The person referred to in section 64(2) may file an application for withdrawal of the assessment order in FORM GST ASMT-17 |
| (5) | 64(2) | The order of withdrawal or, as the case may be, rejection of the application issued in FORM GST ASMT-18 |
Rule 102: special audit
- Sub-rule (1). Where special audit is required under section 66, the officer referred to in that section issues a direction in FORM GST ADT-03 to the registered person "to get his records audited by a chartered accountant or a cost accountant specified in the said direction".
- Sub-rule (2). On conclusion of the special audit, the registered person is informed of the findings in FORM GST ADT-04.
Rules 99, 100 and 102 side by side
| Rule | Subject | Forms | Period printed |
|---|---|---|---|
| 99 | Scrutiny of returns | ASMT-10, ASMT-11, ASMT-12 | Explanation within a time not exceeding thirty days from service of the notice, or such further period as permitted |
| 100 | Assessment in certain cases | ASMT-13 to ASMT-18, DRC-01, DRC-07 | Fifteen days to reply to the ASMT-14 notice |
| 102 | Special audit | ADT-03, ADT-04 | None printed |
Who does what, by when
| Who | What | Form | When |
|---|---|---|---|
| Proper officer | Notice of discrepancy | FORM GST ASMT-10 | After scrutiny of the return |
| Registered person | Accepts and pays, or explains | FORM GST ASMT-11 | Within the time in the notice, not exceeding thirty days from service, or further period permitted |
| Proper officer | Informs that the explanation is acceptable | FORM GST ASMT-12 | After the explanation |
| Proper officer | Assessment notice to a taxable person | FORM GST ASMT-14 and DRC-01 summary | Reply allowed in fifteen days |
| Proper officer | Orders | FORM GST ASMT-13, ASMT-15, ASMT-16, ASMT-18 | As the sections provide |
| Person under section 64(2) | Application for withdrawal | FORM GST ASMT-17 | As section 64(2) provides |
| Officer under section 66 | Special audit direction | FORM GST ADT-03 | As section 66 provides |
| Registered person | Informed of findings | FORM GST ADT-04 | On conclusion |
A worked example
Crestline Foods, an invented registered person, receives a notice in FORM GST ASMT-10 on a discrepancy in a return. The notice seeks an explanation within a stated time, not exceeding thirty days from service unless the officer permits a further period, and quantifies the tax and interest where possible. Crestline checks and accepts part of the discrepancy, pays that tax and interest, and furnishes an explanation for the rest in FORM GST ASMT-11. If the proper officer finds the explanation acceptable, he informs Crestline in FORM GST ASMT-12.
Separately, for a taxable person who is the subject of an assessment under section 63, the officer issues FORM GST ASMT-14 with the grounds and serves a FORM GST DRC-01 summary, allows fifteen days for a reply and passes an order in FORM GST ASMT-15; the summary of the order is uploaded in FORM GST DRC-07. The example uses no amounts; the rules print none.
Points to watch
- Thirty days is the ceiling in rule 99(1) unless the officer permits a further period.
- Fifteen days in rule 100(2) is the fixed reply time for the section 63 notice.
- Summaries. Orders under rule 100(1), (2) and (3) carry a summary in FORM GST DRC-07.
- Special audit is by a chartered accountant or a cost accountant specified in the direction.
- Rule 101 is separate; it covers audit under section 65.
Need help with a scrutiny notice or an assessment order?
A notice in FORM GST ASMT-10 has a short reply window, and the order that follows depends on what the reply shows. We read the notice, reconcile the figures and prepare the reply or the payment. See our GST notices and litigation service.
Key takeaways
- Rule 99: ASMT-10 notice, ASMT-11 reply or payment, ASMT-12 acceptance; explanation within a time not exceeding thirty days.
- Rule 100: ASMT-13 to ASMT-18 for assessment under sections 62, 63 and 64, with a fifteen day reply period in sub-rule (2).
- Summaries of the assessment orders are uploaded in FORM GST DRC-07.
- Rule 102: ADT-03 direction for special audit and ADT-04 findings.
- Rule 101, on audit, is separate.
Read next
- Rule 98 of the CGST Rules, 2017: provisional assessment
- Rules 103 to 107A of the CGST Rules, 2017: advance ruling
- Section 61: scrutiny and the thirty-day reply
- Section 66: special audit
Disclaimer: Based on the Central Goods and Services Tax Rules, 2017 and the GST Acts as amended up to 31 October 2025 in the compilation consulted, read with the Finance Act, 2026 where this article says so, as consulted on 2 October 2026. Notifications, circulars and amendments issued after that date, the forms on the common portal and the way the tax authorities apply these provisions should be checked. This article is general information, not legal advice; check the official text before acting.