Form 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.
Form No. 166 is the statement in which a reporting financial institution gives the tax department the accounts it has identified as reportable. Part A describes the statement and the institution; Part B reports each account, with branch, balances, income, account holder and controlling person details. This guide explains the form as printed in the Income-tax Rules, 2026 (G.S.R. 198(E), notified on 20 March 2026), read with the amending notifications issued up to 22 September 2026.
Under rule 239(8) to (10), the statement required under section 508(1)(k) is furnished by a reporting financial institution for each reportable account; where none is identified, a nil statement is furnished. It is in Form No. 166 "for every calendar year by the 31st day of May following that year", sent by online transmission under digital signature to the Director of Income-tax (Intelligence and Criminal Investigation) or the Joint Director. Under sub-rule (11) it is signed, verified and furnished by the Designated Director.
The section and the rule
Section 508(1) of the Income-tax Act, 2025 requires a long list of persons to furnish a statement about specified financial transactions or reportable accounts that they register or maintain, where the information is relevant for the Act. Clause (k) is "a prescribed reporting financial institution". The statement is furnished for such period, within such time and in such form and manner as is prescribed (sub-section (2)). The section is explained in section 508 on the statement of financial transaction or reportable account. The sister form for specified financial transactions is Form No. 165.
Rule 239 is long and is explained in rule 239 on the information to be reported. This article takes only what bears on the form. Sub-rule (8): the statement is furnished for each account identified as reportable, following the due diligence procedure in rule 240, and a nil statement is furnished where no account is identified. Sub-rule (9): it is in Form No. 166, in the manner specified by the Principal Director General of Income-tax (Systems) or the Director General of Income-tax (Systems) with the Board's approval, for every calendar year by the 31st day of May following that year. Sub-rule (10): it goes to the Director of Income-tax (Intelligence and Criminal Investigation) or the Joint Director by online transmission under digital signature to a designated server, in the data structure specified. Sub-rule (11): the institution communicates the Designated Director's and Principal Officer's details and obtains a registration number, and the Designated Director signs, verifies and furnishes the statement (a person with a valid power of attorney from the Designated Director may do so for a non-resident institution). The due diligence procedures begin in rule 240 and are not explained here.
If you work with a financial institution's compliance team and need help reconciling account data to what is reported, our AIS and TIS reconciliation service looks at the same information from the taxpayer's side.
The form at a glance
The form is a list of fields, each with an identifier, and many ask for a code. It is organised as follows.
| Block | Fields | What it covers |
|---|---|---|
| A.1 Reporting entity details | A.1.1 to A.1.5 | Name, Income-tax Department Reporting Entity Identification Number, Global Intermediary Identification Number (GIIN), registration number, reporting entity category (2-character code) |
| A.2 Statement details | A.2.1 to A.2.8 | Statement type, statement number, original statement id, reason for correction, statement date, reporting period, report types, number of reports |
| A.3 Principal officer details | A.3.1 to A.3.11 | Name, designation, address, city, postal code, state and country codes, telephone, mobile, fax, email |
| B.1 Account details | B.1.1 to B.1.16 | Report serial number, original report serial number, account type, number, category, number type, holder name, status, treatment, equity interest type, self-certification, documentation status, joint account and number of holders, date of closure, currency |
| B.2 Branch details | B.2.1 to B.2.12 | Branch number type, reference number, name, address, city, postal code, state and country codes, telephone, mobile, fax, email |
| B.3 Account summary | B.3.1 to B.3.7 | Account balance or value at the end of the reporting period; aggregate gross interest, dividend, proceeds from sale of property and other income paid or credited; aggregate gross amount credited and debited |
| B.4 Individual details | B.4.1 to B.4.27 | For an individual account holder: name, customer ID, father's and spouse's names, gender, PAN, Aadhaar number, identification, occupation, birth date, nationality, country of residence as per tax laws, place and country of birth, Tax Identification Number and issuing country, address, contact numbers, remarks |
| B.5 Legal entity details | B.5.1 to B.5.25 | For an entity account holder: name, customer ID, account holder types for U.S. and other reportable persons, constitution type, date of incorporation, nature of business, PAN, identification, place and country of incorporation, residence, TIN, address, contacts, remarks |
| B.6 Controlling person details | B.6.1 to B.6.28 | For each controlling person of the entity: type (3-character code), name, customer ID, relatives' names, gender, PAN, Aadhaar, identification, self-certification, occupation, birth date, nationality, residence, birth place and country, TIN, address, contacts, remarks |
Part A's text says the information is provided for each Statement of Reports submitted together. Part B's text says it is provided for each account being reported, with B.1 for each person being reported, B.4 for an individual account holder, B.5 for an entity account holder and B.6 for each controlling person of the entity.
Corrigendum applied
The corrigendum to the Rules (G.S.R. 286(E)) corrects Part A.1: the second entry numbered "A.1.3" (the registration number, above A.1.5) is substituted by "A.1.4". Read the numbering as A.1.1, A.1.2, A.1.3 (GIIN), A.1.4 (registration number) and A.1.5.
The form carries no verification block of its own. The statement is signed, verified and furnished by the Designated Director under rule 239(11)(b). The form's references to codes (for example 1, 2 or 3 character codes) are to the code lists issued with the data structure; the rule leaves the manner to the Principal Director General or Director General of Income-tax (Systems), and those lists are not in the text consulted.
An example
Silverline Bank Limited has identified, through its due diligence under rule 240, accounts held by tax residents of other countries. For the calendar year, it prepares one Form No. 166: Part A with its entity details, a statement number, the reporting period and the number of reports; then, for each reportable account, a Part B report with account, branch, summary and the individual or entity block and controlling person block as needed. Its Designated Director signs and verifies the statement and it is transmitted under digital signature by the 31st day of May following the calendar year. Had no account been identified, it would furnish a nil statement.
Need help understanding reportable account information?
The data in Form No. 166 comes from the institution's records, but the same accounts can show up in a taxpayer's information statements. Our AIS and TIS reconciliation team can help you read and reconcile what is reported about you.
Key takeaways
- Form No. 166 is the Statement of Reportable Account under section 508(1) by a reporting financial institution.
- Rule 239(9) says it is furnished for every calendar year by the 31st day of May following that year.
- Where no account is reportable, a nil statement is furnished (rule 239(8)).
- Part A describes the institution, the statement and the principal officer; Part B reports each account with branch, summary, holder and controlling person details.
- The Designated Director signs and verifies, and it goes by online transmission under digital signature.
Read next
- Rule 239: information to be reported, Form No. 166 and reportable account
- Section 508: statement of financial transaction or reportable account
- Form No. 167: statement of crypto-asset transactions
- Form No. 162: annual statement of a liaison office of a non-resident
Disclaimer: Based on the Income-tax Rules, 2026 (G.S.R. 198(E), notified on 20 March 2026), read with the amending notifications issued up to 22 September 2026, as consulted on 4 October 2026. It explains the words of the forms and rules only; later notifications, the forms and utilities on the e-filing portal, circulars 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.