ITR Filing 2026: 7 Common Mistakes That Can Trigger an Income Tax Notice or Delay Your Refund

Filing an Income Tax Return (ITR) is a fundamental financial responsibility for millions of working professionals and business owners across India. While the e-filing portal has become significantly automated and user-friendly over the years with pre-filled fields, it has also made the Income Tax Department's automated tracking algorithms incredibly sharp.

Even a minor discrepancy between your reported numbers and the department's database can halt the processing of your return. To save yourself from unnecessary anxiety and potential penalties, financial planners emphasize taking a structured approach to avoid seven incredibly common tax-season blunders.

1. Selecting the Wrong ITR Form

The foundation of a successful tax filing rests entirely on choosing the right form based on your specific financial profile. The department provides multiple forms (ranging from ITR-1 to ITR-4 for ordinary individuals) tailored to distinct income streams.

For instance, while a simple salaried individual with a single house property uses ITR-1 (Sahaj), the moment they hold unlisted equity shares, own cryptocurrency, or have capital gains from selling stocks, they must step up to ITR-2. Filing your taxes using the wrong form automatically rendering your return "defective" under Section 139(9), forcing you to completely re-file from scratch.

2. Ignoring Internal Data Inconsistencies (Form 26AS & AIS)

One of the most frequent causes of an automated IT notice is a direct mismatch between what a taxpayer claims in their return and what third-party financial institutions have logged against their PAN.

Before hitting submit, every taxpayer must download and meticulously reconcile three distinct background documents:

• Form 26AS: Tracks all Tax Deducted at Source (TDS) and Tax Collected at Source (TCS) by employers and vendors.
  
• Annual Information Statement (AIS): A comprehensive ledger tracking high-value transactions like stock market purchases, mutual fund investments, and credit card spending.
  
• Taxpayer Information Summary (TIS): A concise, aggregated summary of your taxable income streams.
  

If your employer reported a specific salary amount but you entered a different figure, or if you failed to report stock dividends recorded in your AIS, the portal's system will immediately flag the mismatch.

3. Overlooking Secondary Sources of Income

Many individuals falsely believe that if an income stream isn't part of their primary monthly salary slip, it doesn't need to be declared. This is a severe mistake.

Taxpayers are legally required to report all forms of secondary income under the head "Income from Other Sources." This includes the interest earned on standard savings bank accounts, recurring deposits, fixed deposits (FDs), corporate bonds, and agricultural or rental revenues. Even minor amounts must be logged, as banks report all interest payouts directly to the tax authorities.