Intimation Under Section 143(1): How to Read It and Fix a Mismatch

An email arrives from the Income Tax Department with a password-protected PDF attached, and the panic is immediate and almost always unwarranted. An intimation under Section 143(1) is not a scrutiny notice, not an accusation, and not a sign that anyone has looked at your affairs with suspicion. It is the automated receipt you get after the Centralised Processing Centre runs your return through a set of arithmetic and cross-verification checks. Most of the time it says the department agrees with you exactly. When it doesn't, the disagreement is usually one line item wide, and the document tells you precisely which line.

Opening the PDF

The attachment is password-protected. The password is your PAN in lower case followed immediately by your date of birth in DDMMYYYY format, with no space or separator between them. So a PAN of ABCDE1234F with a date of birth of 7 March 1990 gives a password of abcde1234f07031990. For a company or firm, use the date of incorporation in the same format. If it refuses to open, the usual culprit is a date of birth on the PAN database that differs from the one you are typing, which is worth correcting separately.

The Only Two Columns That Matter

Skip past the covering pages. The heart of the intimation is a table with two numeric columns set side by side: one headed along the lines of "as provided by taxpayer in return of income" and the other "as computed under Section 143(1)." Read across each row. Wherever the two numbers are identical, there is nothing to do. Wherever they diverge, that single row is the entire dispute, and the final rows will tell you whether the result is a refund, a demand, or neither.

Where Mismatches Actually Come From

Processing at CPC is largely mechanical, so mismatches cluster around a short list of causes. Recognising yours saves a great deal of time.

• TDS claimed in your return that does not appear against your PAN in Form 26AS, usually because a deductor filed their TDS return late, quoted the wrong PAN, or tagged the credit to a different year.
• Advance tax or self-assessment tax paid correctly but tagged to the wrong assessment year or the wrong PAN on the challan, so the system cannot find it.
• A deduction claimed in the return that never went through your employer and therefore does not appear in Form 16, which the system frequently declines to allow at processing stage.
• Section 89 relief on salary arrears claimed in the return without Form 10E being filed first, which gets the relief disallowed almost automatically.
• A tax regime applied differently from what you intended, which usually traces back to how the option was recorded in the return or to Form 10-IEA where it was required.
• Income visible in your AIS, such as savings bank interest, dividend, or interest on an earlier year's refund, that was left out of the return.
• A carried-forward loss disallowed because the return for the loss year was filed after the due date, which forfeits the carry forward for most heads of income.

Agree or Disagree: Rectification Versus Revised Return

This is the decision people get wrong most often, and choosing the wrong route wastes weeks. The test is simple: ask whether the mistake is in the department's processing or in the return you filed.

To respond to a demand, go to Pending Actions and then Response to Outstanding Demand on the e-filing portal, open the entry for that assessment year, and select whether you agree or disagree. Where you disagree, pick the specific reason offered and attach your supporting document, typically the challan for a payment that was not recognised or the corrected Form 26AS. Do this within the time stated in the intimation, usually 30 days, because a demand left unanswered hardens into a recoverable one and can be set off against a later year's refund under Section 245.

The Deadlines Worth Knowing

The department must issue the Section 143(1) intimation within nine months from the end of the financial year in which you furnished the return. A return filed in July 2026 falls in FY 2026-27, so that outer limit runs to 31 December 2027. If the window closes without any intimation being issued, your return is deemed accepted exactly as filed and the acknowledgement itself serves as the intimation. Going the other way, a rectification application under Section 154 can generally be made within four years from the end of the financial year in which the order you want corrected was passed, which is a far longer runway than the revised return window and is why the rectification route matters. One point of terminology for the years ahead: the Income Tax Act, 2025 has renumbered these provisions, but returns covering income earned before 1 April 2026 continue to be processed under the 1961 Act, so intimations you receive this year will still carry the familiar 143(1) and 154 references.