A comprehensive reference guide covering all major tax compliance requirements for businesses in India — ITR, GST, TDS, audit, and transfer pricing deadlines for 2026.
Income Tax Compliance — Key Obligations and Deadlines
Business entities in India face multiple annual income tax compliance obligations, each with specific deadlines that attract penalty and interest on default. Corporate entities must file their income tax return by October 31 of the assessment year (November 30 for companies with international transactions requiring Form 3CEB). Advance tax must be paid in four instalments throughout the financial year. Tax Audit under Section 44AB is mandatory for businesses with turnover exceeding Rs 1 crore (Rs 10 crore if 95% or more of transactions are digital) and for professionals with gross receipts exceeding Rs 50 lakh.
The Tax Audit Report (Form 3CD) must be signed by a Chartered Accountant and uploaded on the income tax portal at least one month before the ITR filing deadline. The form requires extensive disclosures including details of cash transactions, loans and deposits, payments to related parties, provisions made, and compliance with Section 40A(3) (cash expenditure limit). Companies that have not maintained adequate documentation for each of these items throughout the year typically face significant work during the audit preparation process in September-October.
GST Compliance Calendar
GST compliance for regular taxpayers involves monthly or quarterly filing obligations depending on turnover. Businesses with annual turnover above Rs 5 crore must file GSTR-1 by the 11th of the following month and GSTR-3B by the 20th. Those below this threshold can opt for the QRMP (Quarterly Return Monthly Payment) scheme, which requires payment of tax monthly (via a fixed-sum or self-assessed challan) and filing of GSTR-1Q and GSTR-3BQ quarterly. Annual return in GSTR-9 (and GSTR-9C reconciliation statement for taxpayers above Rs 5 crore) is due by December 31 following the end of the financial year.
E-invoicing is mandatory for businesses above the applicable turnover threshold (currently Rs 5 crore, with expectations of further reduction). Each invoice must be uploaded to the Invoice Registration Portal (IRP) to obtain an Invoice Reference Number (IRN) and a digitally signed QR code before the invoice is sent to the buyer. Failure to generate an IRN renders the invoice invalid for ITC purposes, and the issuance of an invoice without IRN attracts penalty. Businesses approaching the e-invoicing threshold should implement IRP-integrated accounting software well before the threshold is crossed to avoid compliance gaps.
TDS, Transfer Pricing, and Other Compliance
Tax Deducted at Source (TDS) obligations arise on payments of salary, interest, professional fees, rent, contract payments, and various other categories, with rates prescribed in the respective sections of the Income Tax Act. TDS must be deducted at the time of credit or payment (whichever is earlier), deposited by the 7th of the following month (except for March, where the deadline is April 30), and quarterly statements filed in Form 26Q (for non-salary TDS) and Form 24Q (for salary TDS). Errors in TDS return filing — incorrect PAN, wrong payment section, or mismatched amounts — create mismatches in the payee's Form 26AS and require revision of the TDS return, which should be done promptly upon detection.
Transfer pricing compliance (Form 3CEB, master file, CbCR) applies to entities with international related party transactions. The documentation must be contemporaneous — prepared before the tax return filing date — rather than reconstructed after the fact. Entities entering into high-value related party transactions should engage transfer pricing specialists by April of the assessment year to ensure that documentation is prepared as transactions occur, pricing benchmarks are established, and the Form 3CEB can be signed and filed well before the deadline. Late or inadequate documentation attracts penalty of 2% of the transaction value under Section 271AA, independent of any adjustment made by the Assessing Officer.
