Getting a reassessment notice under Section 148: the show-cause step and your response window

A reassessment notice is one of the few pieces of post from the Income Tax Department that carries a hard clock the moment you open it. Under the framework running from 1 September 2024, the department cannot simply reopen a closed year; it must first put its information to you through a show-cause step under section 148A, and only then issue the notice under section 148 that reopens the assessment year. This piece walks through what each stage means, the exact window you get to respond, and how to compute your deadline from the date printed on the notice.

The Scenario

Picture an assessee, a salaried professional who declared Rs 18 lakh of income in her income tax return for a past year, opening the e-filing portal in March 2026 to find an intimation that her case is being reopened. The letter refers to "information suggesting that income chargeable to tax has escaped assessment" and asks her to explain, within a stated number of days, why a notice under section 148 should not be issued. She has not been accused of anything; she has been given a chance to answer first. That first letter is the section 148A show-cause notice.

The confusion most taxpayers feel at this point is procedural rather than moral. They do not know whether the clock has already started, whether the reopening is even valid on timing grounds, or how long they have to file the return the department wants. Getting these three things right, the validity of the reopening, the response window on the show-cause step, and the return-filing window after the section 148 notice, is what separates a clean resolution from an ex-parte order passed for non-compliance. The official Income Tax Department FAQ on reassessment proceedings sets out this sequence explicitly, and it is the anchor for everything below.

Statutory Answer

The governing rule is that a reassessment cannot begin with the section 148 notice. Per the Income Tax Department's reassessment FAQ, before any notice under section 148 is issued the Assessing Officer must first give the assessee an opportunity of being heard through a show-cause notice under section 148A. That notice must set out the information that suggests income has escaped assessment and allow the taxpayer time to respond before any decision is taken. Skipping this step is a recognised ground on which reopenings have been quashed, so the order in which the two notices arrive matters.

Approval is not left to a single officer acting alone. The FAQ confirms that the specified authority for the purposes of sections 148 and 148A is an Additional Commissioner, Additional Director, Joint Commissioner or Joint Director. In practice this means the file must be signed off at that rank before either the show-cause notice or the reopening notice can validly go out, which is one of the first things a representative checks on receiving the papers.

Once the Assessing Officer has considered your reply and decided to proceed, the section 148 notice is issued, and a second clock starts. The FAQ states that the return must be furnished within the time specified in the notice, which cannot exceed three months from the end of the month in which the notice under section 148 is issued. So the outer limit for filing your reassessment return is fixed by the calendar month of the notice, not by the day it lands in your inbox.

Whether the year can be reopened at all is decided by the time limits in section 149 of the Income Tax Act 1961. The threshold figure that unlocks the longer window is Rs 50 lakh: where the Assessing Officer has evidence that the income escaping assessment, represented in the form of an asset, expenditure or an entry, amounts to or is likely to amount to Rs 50 lakh or more, the extended period applies; below that, only the ordinary period is available. The two regimes work as follows.

One transition point matters for anyone whose reopening straddles the change in law. The Income Tax Act, 2025 takes effect from 1 April 2026, but the FAQ makes clear that reassessment proceedings already initiated under the Income Tax Act, 1961 continue to be governed by the 1961 Act framework under the transition and grandfather provisions. A notice validly issued in, say, February 2026 does not migrate to the new statute midway; it runs to completion under the law it began under.

Worked Resolution

Take the salaried assessee above and put concrete dates on the two clocks. Assume the section 148A show-cause notice is dated 5 February 2026 and gives her the commonly specified window to reply. She uses that window to file her response on the portal, attaching bank statements to explain the transaction the department flagged. The Assessing Officer, unpersuaded, obtains approval from the Joint Commissioner and issues the section 148 notice on 15 March 2026.

Her return-filing deadline is now driven by a single sentence in the statute: no more than three months from the end of the month in which the section 148 notice is issued. The notice is dated in March 2026, so the clock starts from 31 March 2026, and three months takes her to 30 June 2026. The table below sets out the computation step by step.

If the reopening had instead concerned an older year, the section 149 question would come first. Suppose the flagged item was an undisclosed property purchase of Rs 62 lakh. Because Rs 62 lakh is above the Rs 50 lakh threshold, and assuming the section 148 notice issued after 1 September 2024, the extended window of 5 years and 3 months from the end of the relevant assessment year is the one to test the notice against; had the escaped income been, say, Rs 40 lakh, only the 3 year and 3 month ordinary window would be open, and a notice outside it would be time-barred.

Two practical steps flow from this. First, respond to the section 148A show-cause notice on the merits rather than ignoring it, because that reply is your first and cheapest chance to stop the reopening. Second, once the section 148 notice arrives, file the reassessment return within the stated window even if you dispute the reopening, because the return protects your position while any challenge to validity is argued separately. You can sanity-check the tax on the reassessed figure using Oquilia's income tax calculator and reconcile any TDS already deducted, so the demand you eventually face reflects credits you have genuinely earned. If the reopening turns on advance-tax shortfalls for the year, the advance tax calculator helps you see the interest exposure before the officer computes it.

FAQ

What is the difference between a section 148A notice and a section 148 notice?

The section 148A notice is the show-cause step: the Assessing Officer must, before reopening, put the information to you and let you respond, per the Income Tax Department's reassessment FAQ. The section 148 notice is the actual reopening notice that requires you to file a return; it can only be issued after the 148A stage and after approval by the specified authority.

How long do I get to file my return after a section 148 notice?

The time cannot exceed three months from the end of the month in which the section 148 notice is issued. For a notice dated anywhere in March 2026, the clock starts on 31 March 2026 and the outer limit is 30 June 2026. Always file within the specific period stated in your notice, which may be shorter.

Who has to approve a reassessment before the notice is issued?

Per the FAQ, the specified authority for sections 148 and 148A is an Additional Commissioner, Additional Director, Joint Commissioner or Joint Director. Approval at this rank is a validity requirement, not a formality, so its absence is a genuine ground of challenge.

How far back can the department go to reopen my assessment?

Under the Finance (No.2) Act 2024 framework for notices issued on or after 1 September 2024, the ordinary limit is 3 years and 3 months from the end of the relevant assessment year, extending to 5 years and 3 months where the escaped income represented as an asset, expenditure or entry is Rs 50 lakh or more. Notices issued on or before 31 August 2024 fall under the earlier 3 year and 10 year limits.

Does the new Income Tax Act, 2025 change a reassessment already in progress?

No. The Income Tax Act, 2025 takes effect from 1 April 2026, but the reassessment FAQ confirms that proceedings already initiated under the Income Tax Act, 1961 continue under that Act's framework by virtue of the transition and grandfather provisions. A notice validly issued before that date runs to completion under the 1961 Act.

What happens if I ignore the section 148 notice?

Not filing the return within the specified window exposes you to a best-judgement assessment made without your inputs and to interest and penalty consequences. Because the section 148 return window is capped at three months from the end of the notice month, the safer course is to file within it even while disputing the reopening, and to reconcile any refund or credit position separately.

Can I still challenge the reopening after I file the reassessment return?

Yes. Filing the return to meet the section 148 deadline does not waive your right to contest whether the reopening satisfies section 149's time limits or the section 148A procedure. The two are argued on separate tracks, which is why practitioners advise complying with the filing clock first and litigating validity second.