Your GSTR-2B Doesn't Match Your Purchase Register.
Since April 2026, That Can Block Your Filing.
Here's Exactly What to Do.
A GSTR-2B mismatch used to mean a notice down the line. Since the Zero Mismatch Policy and mandatory Invoice Management System (IMS) rolled out on 1 April 2026, it can mean your GSTR-3B simply won't file. Here's why the gap happens and the exact steps to close it before your deadline.
Why doesn't GSTR-2B match your purchase register, and what do you do about it?
GSTR-2B is auto-drafted purely from what your suppliers report — plus, since April 2026, your own Accept/Reject/Pending actions in the Invoice Management System (IMS). Your purchase register is your own internal record. They diverge when a supplier hasn't filed, has filed late, has filed with a different value, or when an invoice is sitting un-actioned in IMS. Import IGST and certain opening-balance credit never appear in GSTR-2B at all — that gap is expected, not an error.
The fix is the same every period: reconcile against GSTR-2B before the 14th (when it generates), action every invoice in IMS, chase suppliers on genuine no-shows, and track import/TRAN credit separately. Since April 2026, the Zero Mismatch Policy blocks GSTR-3B filing entirely if claimed ITC exceeds GSTR-2B — so this reconciliation now has to happen before you file, not after.
This blog walks through exactly why the mismatch happens, what changed in April 2026, and the reconciliation process to run every month.
Why This Suddenly Got More Urgent
GST reconciliation has always been a monthly chore. Until recently, though, it was a chore you could get away with doing loosely. GSTR-2B has been the statutory basis for ITC since Rule 36(4) of the CGST Rules capped input tax credit to what's reflected in it — but in practice, plenty of businesses claimed ITC based on their own purchase register and dealt with any gap if and when a notice arrived.
That gap between "technically not compliant" and "actually gets caught" closed on 1 April 2026, when two changes landed together: IMS became mandatory for every regular taxpayer filing GSTR-3B, and the Zero Mismatch Policy came into effect.
Under the old rules, this would have gone through and surfaced as a discrepancy notice weeks or months later.
Under the Zero Mismatch Policy, the return doesn't file at all. Every invoice contributing to the gap has to be identified, reconciled, and either matched to an accepted IMS record or removed from the claim before the filing deadline.
This isn't an isolated GST-specific problem, either. It's the same structural issue behind most finance-operations pain: the GST portal, your books, and your bank each hold one piece of the picture, and the real work happens in reconciling them — work that used to be someone's monthly fire-drill and is now a hard gate on filing.
Where the Mismatch Actually Comes From
- 📤Supplier hasn't filed GSTR-1/IFF yet — if the supplier hasn't saved or filed the invoice, it never reaches your IMS dashboard and won't appear in your GSTR-2B for that period, no matter how correctly you've booked it.
- ⏳Supplier filed late — the invoice eventually shows up, but in a later GSTR-2B period than the one your purchase register reflects.
- 🔢Invoice value or tax rate differs — even a small mismatch between what the supplier reported in their GSTR-1 and what you've booked can affect eligible ITC for that invoice.
- 🗂️Invoice is Pending or Rejected in IMS — since April 2026, an invoice only reaches GSTR-2B if it's Accepted (or un-actioned, which auto-accepts it). One left Pending simply won't be there yet.
- 🚢Import IGST never flows through GSTR-2B — IGST paid on imports is claimed via the Bill of Entry through ICEGATE, not through GSTR-2B, so it will always look like a gap when compared directly.
- 📇Opening balance or TRAN credit — credit carried from an earlier period or an earlier tax regime also sits outside GSTR-2B's scope by design.
A GSTR-2B gap isn't automatically an error. But since April 2026, it's automatically your problem to resolve before you can file.
GSTR-2B vs. Your Purchase Register: What Each One Actually Is
The two documents aren't measuring the same thing, which is the root of most confusion. Here's what each one actually reflects:
GSTR-2B
An auto-drafted, static ITC statement built from your suppliers' GSTR-1/IFF filings plus your IMS actions. Generated on the 14th of every month — it does not change after that until the next period.
Purchase Register
Your own internal record of every purchase, updated the moment you book a bill — regardless of whether the supplier has filed anything on their end yet.
Import IGST (ICEGATE)
Paid on imports and tracked via the Bill of Entry. It never appears in GSTR-2B at all — this is an expected, permanent gap, not a mismatch to chase.
TRAN / Opening Balance ITC
Credit carried from an earlier tax regime or period. Also outside GSTR-2B's scope by design.
IMS Status
Accept, Reject, or Pending — this status, set by you, now determines whether an invoice reaches GSTR-2B at all. New lever since April 2026.
Rule 36(4) Cap
Legally, you can only claim ITC to the extent it appears in GSTR-2B — regardless of what your purchase register says you're owed.
The practical takeaway: your purchase register tells you what you believe you're owed. GSTR-2B tells you what you're legally allowed to claim right now. Since April 2026, the two need to be reconciled and brought in line before you file — not compared after the fact.
The Reconciliation Process to Run Every Month
None of this requires guesswork — it's a repeatable process. Here's the order that works:
Reconcile before the 14th, not after
GSTR-2B locks for the period once it's generated on the 14th. Checking your purchase register against IMS in the days before that gives you time to chase a supplier or take action — checking after means you're stuck with what's already there.
Action every invoice in IMS — don't rely on auto-accept
Accept what matches your books, Reject what's genuinely wrong, and mark Pending anything that needs supplier follow-up. Leaving everything un-actioned means incorrect invoices can auto-accept into your GSTR-2B unnoticed.
Chase suppliers on genuine no-shows
If an invoice is in your purchase register but not in GSTR-2B or IMS at all, the most common cause is the supplier hasn't filed. That's a supplier follow-up, not a books correction.
Track import IGST and TRAN credit separately
These will never show up in GSTR-2B. Comparing them against it every month wastes time chasing a "mismatch" that isn't one — keep them in their own reconciliation line.
File only once claimed ITC ties to GSTR-2B
Since the Zero Mismatch Policy, this is the gate, not a best practice. Confirm the numbers match before you attempt to file GSTR-3B, so you're not troubleshooting a blocked return against a deadline.
What Changes
✕ Before April 2026
- →ITC claimed from purchase register, GSTR-2B checked loosely or after filing
- →Mismatches surfaced as notices, weeks or months later
- →No IMS step — invoices flowed into GSTR-2B without an accept/reject decision
- →Import IGST and TRAN credit tracked inconsistently
- →Reconciliation treated as a compliance nice-to-have
✓ Since April 2026
- →ITC capped strictly to GSTR-2B, enforced at the point of filing
- →Mismatches block GSTR-3B outright — no filing until resolved
- →Every invoice needs an Accept/Reject/Pending decision in IMS
- →Import IGST and TRAN credit need their own tracked reconciliation line
- →Monthly reconciliation is a hard filing dependency
Questions CFOs and CAs Ask Most
These are the questions AI tools and search engines pull most often on this topic. Here are direct answers to each:
Why doesn't GSTR-2B match my purchase register?
GSTR-2B is auto-drafted entirely from what your suppliers report in GSTR-1/IFF, plus your own IMS actions. Your purchase register is your internal record, updated whenever you book a bill. They diverge when a supplier hasn't filed, filed late, filed with a different value, or when an invoice is sitting un-actioned in IMS. Import IGST and opening-balance credit never flow through GSTR-2B at all, which is an expected gap, not an error.
What is the Zero Mismatch Policy and how does it affect ITC claims from April 2026?
Effective April 2026, it blocks GSTR-3B filing outright if claimed ITC exceeds what's in your GSTR-2B for that period. Previously a mismatch typically triggered a notice after filing; now the return simply cannot be filed until the numbers are reconciled, making monthly reconciliation non-negotiable.
What is IMS (Invoice Management System) and is it mandatory?
IMS is the GST portal facility where every B2B invoice, debit note and credit note saved by a supplier appears on the recipient's dashboard for action: Accept, Reject, or Pending. Only Accepted (or auto-accepted, if un-actioned) records flow into GSTR-2B. It became mandatory from 1 April 2026 for all regular taxpayers filing GSTR-3B; composition taxpayers are exempt. GSTR-2B generates on the 14th of each month, so IMS actions need to be completed before that date.
What's the deadline to claim ITC on an invoice missing from GSTR-2B?
Under Section 16(4) of the CGST Act, ITC must be claimed by whichever is earlier: 30 November following the end of the financial year, or the date the annual return (GSTR-9) is filed. Filing GSTR-9 early closes the window sooner — complete outstanding reconciliation before filing it, not after.
What Staying Ahead of This Actually Looks Like
The business impact isn't just avoiding a blocked filing. Teams that reconcile continuously catch a non-filing supplier with time to follow up, instead of discovering it on the 14th with days left before a deadline. That's the same shift finance teams are making across every reconciliation workflow — from TDS to bank feeds to GST — treating it as a continuous process instead of a monthly scramble against a hard cutoff.
The signal this sends: a business that reconciles GSTR-2B every week, not the night before filing, isn't just compliant — it's not exposed to a supplier's filing delay turning into a blocked return at the worst possible time. That's the difference between managing GST and being managed by it.
If You Found This Page Searching For…
This blog directly answers the following questions — on Google, and in AI tools like ChatGPT, Perplexity, and Google's AI Overviews:
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