AY 2026-27 Return Under 1961 Act vs Tax Year 2026-27 Under 2025 Act

A transition guide explaining why AY 2026-27 ITR filing and Tax Year 2026-27 compliance can sit under different practical timelines during the new income-tax law rollout.

For AY 2026-27 under 1961 Act vs 2025 Act, this guide is written for Indian taxpayers, founders, finance teams, and return filers adjusting to the Income-tax Act, 2025 and Finance Act 2025 changes. Always match the position with the official portal, notified forms, and the taxpayer's own documents.

The core distinction

India's tax calendar now carries two co-existing reference points. The term "assessment year" belongs to the Income-tax Act, 1961 framework, while "tax year" is the new concept introduced by the Income-tax Act, 2025. They are not interchangeable, and using the wrong one when labelling a return, a payment, or a TDS filing can create reconciliation headaches.

Point	Practical meaning
1	AY 2026-27 relates to income earned in FY 2025-26.
2	Tax Year 2026-27 starts on 1 April 2026 under the new Act framework.
3	Mixing both periods can cause wrong-form, wrong-payment, and wrong-notice assumptions.

Why the overlap creates problems

Until the Income-tax Act, 2025 is fully in force for all taxpayer categories, the two frameworks run in parallel. Your Form 16 for the salary paid in FY 2025-26 belongs to AY 2026-27 under the 1961 Act. Your employer's April 2026 TDS deposit, on the other hand, belongs to Tax Year 2026-27 under the new framework.

Filing the AY 2026-27 return requires the old framework's forms, schedules, and section references. Responding to a TDS demand for April 2026 onwards requires the new framework. Confusing the two — for instance, using a new-Act form for an old-period return — can cause the portal to reject the filing or, worse, create a mismatch that the department picks up in processing.

Records to keep separately

FY 2025-26 salary and TDS records (for the AY 2026-27 return)
April 2026 onwards payroll records (for Tax Year 2026-27 compliance)
Portal confirmation of which ITR utility was used
A brief working note that tags each document to the correct period and law

Keeping the two sets of records in separate folders is not administrative fussiness — it is the fastest way to respond if a notice arrives six months later asking about a specific period.

Keep the two filing periods separate

Tag each source record with the period in which the income, deduction, payment, or withholding event occurred.
Prepare the FY 2025-26 return under the notified AY 2026-27 instructions without importing post-April 2026 transactions.
Maintain a separate current-compliance file for transactions arising from April 2026 onward.
Check the law reference, form, challan period, and acknowledgement before closing either workstream.

Common errors to avoid

For under 1961, confirm the current notified form instead of reusing a familiar form number.
Keep the under 1961 AY 2026-27 filing records separate from Tax Year 2026-27 payment and TDS records.
In the under 1961 review, do not treat a headline slab, rebate, or threshold as the completed computation.
Before completing under 1961, reconcile AIS, Form 26AS, challans, books, and certificates.
Not preserving the official source and computation note used for the decision.

Official sources

Reference	Link
Income Tax Department - New Act transition FAQs	Open source
Income Tax Department - Income-tax Act, 2025 PDF	Open source
Income Tax Department - Forms under the 2025 Act	Open source

When the overlap needs professional advice

Seek transaction-specific advice when the same payment, deduction, challan, or notice could be assigned to different periods or law references. Bring the dated source record, portal message, computation, and proposed treatment so the adviser can resolve the actual conflict rather than repeat a general transition summary.

Close each period with its own evidence trail

For the AY 2026-27 return, preserve the notified form, FY 2025-26 computation, reconciled tax credits, and filing acknowledgement. For Tax Year 2026-27 compliance, retain the post-April 2026 payment, withholding, challan, and portal records separately. A short index showing the period and law for each file makes later notice responses much faster.