Form 26AS, AIS & TIS: What's the Difference? Before you file your income tax return, three documents on the income tax portal tell the department what it already knows about your money: Form 26AS, the AIS (Annual Information Statement) and the TIS (Taxpayer Information Summary). Reading them — and fixing any mismatch — is the single best way to avoid a tax notice. This guide explains what each one shows and how to use them, in plain language for FY 2025-26 (AY 2026-27).