Client documents checklist a CA firm should collect before the Oct 2026 GST/TDS crunch
Short answer: before mid-to-late October, ask each client for the papers tied to one deadline at a time — GSTR-3B (20 Oct monthly / 22 Oct QRMP for Telangana and AP), the tax-audit report (21 Oct for covered cases), and Q2 TDS/TCS statements (31 Oct). One short list per form beats a vague “send everything” message.
Why this week matters
Three compliance blocks pile up in the second half of October 2026. Firms that wait until the due date for documents lose filing days to chases. Send the list now; file when the pack is complete.
| Deadline | Date (Oct 2026) | Who |
|---|---|---|
| GSTR-3B (monthly, Sep period) | 20 Oct | Monthly GST filers |
| GSTR-3B (QRMP, Jul–Sep) | 22 Oct (TG, AP) or 24 Oct (other QRMP states) | QRMP filers by state group |
| Tax-audit report (Form 3CA/3CB + 3CD) | 21 Oct (per CBDT Circular 07/2026, non-TP cases) | Assessees under tax audit |
| Q2 TDS/TCS statements | 31 Oct | Deductors / collectors (Forms 138, 140, 144, 143) |
1. Documents for GSTR-3B (ask ~7 days before)
- Sales register or GSTR-1 / IFF data for the period (invoice-wise outward supplies)
- Purchase invoices and e-way bills needed to claim ITC; mark ineligible or blocked credit
- Debit notes / credit notes still open for the period
- Bank statement or payment proof for GST already paid / to be paid
- Nil confirmation in writing if there were no supplies (so you can file nil on time)
- For QRMP: state group (22nd vs 24th) and any PMT-06 challans already paid in the quarter
Related: GSTR-3B due dates for October 2026 · QRMP 22nd/24th state groups.
2. Documents for the tax-audit report (due 21 Oct 2026)
- Books of account for FY 2025-26 (or the relevant previous year) and trial balance
- Stock register / inventory valuation workings and fixed-asset register with additions/deletions
- Bank reconciliations and loan / creditor confirmations
- GST vs books reconciliation (outward, inward, ITC)
- Form 3CD clause inputs your firm uses (related-party, payments covered by TDS, etc.)
- Copy of any CBDT / portal notice the client received about the audit due date
Related: Tax-audit report due date 21 October 2026.
3. Documents for Q2 TDS/TCS statements (due 31 Oct 2026)
- Challan details (BSR, challan serial, date, amount) for TDS/TCS deposited for Jul–Sep 2026
- Party-wise deduction / collection list with PAN, section code, and amount
- Lower or nil deduction certificates and any Form 15G/15H where used
- Mapping notes if staff still mix old Form 26Q-style labels with new Form 140 section codes
- Confirmation that March-style special deposit dates do not apply to this quarter’s rows
Related: Q2 TDS return due dates · Form 26Q → Form 140 section mapping.
How to ask (copy-paste template)
Keep it to two lines. Name the form and the date. List only what is missing:
- “GSTR-3B for Sep is due 20 Oct. Please send sales register, purchase invoices for ITC, and bank proof for GST by 15 Oct. Reply ‘nil’ if no supplies.”
- “Tax-audit report is due 21 Oct. We still need: stock register, bank reconciliations, GST vs books recon. Please share by 17 Oct.”
- “Q2 TDS statement is due 31 Oct. Please send Jul–Sep challan list and party-wise PAN / section sheet by 24 Oct.”
For a full reminder rhythm, see the free client deadline reminder system for CA firms.
Common mistakes in the document chase
- One mega list for every client. Monthly GST and tax-audit clients need different packs.
- Asking on the due date. Leave at least five working days for incomplete PANs and missing challans.
- Ignoring QRMP state groups. Telangana and AP are on the 22nd; other QRMP states may be on the 24th.
- No nil option. Make it easy for a quiet month so a nil return still goes in on time.
Frequently asked questions
What documents should a CA firm collect before GSTR-3B in October 2026?
Ask for the sales register or GSTR-1 data for the period, purchase invoices and e-way bills needed for ITC, bank statements covering GST payments, and any debit or credit notes still open. For monthly filers the GSTR-3B due date is 20 October 2026 for September; for QRMP filers in Telangana and Andhra Pradesh the quarterly return is due 22 October 2026.
What should clients send before the tax-audit report due on 21 October 2026?
For non-transfer-pricing audit cases covered by CBDT Circular 07/2026, collect books of account, stock and fixed-asset registers, Form 3CD working-paper inputs, bank reconciliations, loan confirmations and GST vs books reconciliation for FY 2025-26.
What do deductors need before Q2 TDS statements on 31 October 2026?
Collect challan details for TDS/TCS deposited for July–September 2026, party-wise deduction lists with PANs and section codes, and certificate or lower-deduction details. Q2 statements (Forms 138, 140, 144 and TCS Form 143) are due 31 October 2026.
Official sources to re-check
- GST portal: GSTR-3B user guide (20th monthly; 22nd/24th quarterly)
- GSTN QRMP advisory (state groups)
- CBDT Circular 07/2026 (tax-audit report and related ITR extensions — confirm on the Income Tax portal)
- Income Tax Department: Form 140 FAQs (quarterly statement due dates)
This guide is general information for CA firms and GST practitioners, not tax advice and not an official government publication. Your firm stays responsible for advice to your clients. Dates move when CBIC, CBDT or the portal publish extensions — always re-check before you file. Last checked 13 Oct 2026.
If you want the dates branded for your firm
You can build a free national date list with the in-browser CA due-date calendar, or start from the free white-label sample. The White-Label Client Compliance Calendar for CA Firms (₹999/year) sends four quarterly packs with your firm name on the DOCX, PDF and WhatsApp image, plus the national .ics/.xlsx and extension updates. Files are made after checkout (not instant). 14-day refund from when you receive the first pack. Disclosure: that is an Unadhi product.
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