What your GST returns reveal that your P&L hides

A profit and loss statement is built on judgement. Revenue recognition timing, expense classification, related-party pricing and provisioning are all choices, made inside the finance function, that shape how the year looks on paper. A GST return is built on something harder to bend: an invoice, a time of supply, and a tax liability that the GST Network records the moment it is filed. Reading both together, side by side, gives a founder a second opinion on their own numbers that no P&L can offer alone. Most founders never run this comparison until an investor’s diligence team or a GST officer runs it for them. By then, the gaps have a paper trail with someone else’s name on it.

Why don’t my GST returns match my P&L?

They are not built to match exactly. Your P&L recognises revenue under accrual accounting principles, while GST liability is triggered by the statutory time of supply under Sections 12 and 13 of the Central Goods and Services Tax (CGST) Act, 2017. Differences from unbilled revenue, advances, exports, or related-party valuation are normal and explainable. An unexplained or growing gap is the signal worth investigating.

Why your P&L and your GST returns are built to disagree

Your P&L and your GST returns are not two versions of the same document. They are two different accounting systems answering two different questions, and a founder who expects them to match line for line is asking for something the law never intended.

Your P&L follows accrual accounting under the Accounting Standards or Ind AS, whichever applies to your company. Revenue is recognised when it is earned, which can mean the moment a service is substantially delivered, even if no invoice has gone out and no cash has moved. Your GST liability follows a completely different trigger: the statutory time of supply, defined under Sections 12 and 13 of the CGST Act, 2017. For services, that is generally the earlier of the invoice date or the date payment is received. For goods, it typically follows the invoice or removal date. Neither definition asks whether revenue has been earned in an accounting sense.

This is why a reconciliation gap is not automatically a red flag. It becomes one when it stops being explainable. Tribunals have consistently held that income in a profit and loss account follows accounting rules, while GST output tax is triggered by the statutory time of supply, so a demand raised purely on a P&L-to-GSTR-3B mismatch, with no evidence of an actual unaccounted supply, does not hold up. The same logic that protects a taxpayer from an arbitrary demand also means the taxpayer cannot wave away every gap as “just timing.” A gap needs a name and a number, every single time.

P&L logic versus GST logic

Dimension	P&L (books)	GST returns
Recognition trigger	Revenue earned, per Ind AS 115 or AS-9	Time of supply, Sections 12 and 13, CGST Act 2017
Related-party sales	Recorded at agreed transfer price	Valued under Section 15(4) read with the CGST Valuation Rules, often at open market value
Advances received	Not revenue until earned	Taxable on receipt for goods in specified cases, generally on invoice for services
Exports and zero-rated supply	Recognised as revenue at invoice or shipment	Reported separately, often with LUT and no output tax
Stock transfers between own GSTINs	No P&L entry, it is the same legal entity	Deemed supply under Schedule I, taxable between distinct persons

The first three rows are the ones that quietly reshape a founder’s read of their own business. The gap between GSTR-1 outward supply value and audited P&L turnover is precisely what Table 5 of GSTR-9C, the reconciliation statement under Rule 80(3) of the CGST Rules, exists to explain. If your finance team cannot produce that explanation on demand, in writing, with figures, you do not actually know why your two systems disagree. You are simply hoping they agree by coincidence.

What unbilled revenue in your GST reconciliation is actually telling you

An unbilled revenue adjustment in your GST reconciliation is a direct measure of how much of your reported profit exists only as an internal journal entry, with no invoice, no GST liability, and often no enforceable claim against the customer yet.

Unbilled revenue is booked in your P&L when work is substantially complete but the invoice has not gone out. This is common and legitimate in project-based businesses, SaaS with milestone billing, and services with month-end cutoffs. It also does not appear anywhere in your GSTR-1 or GSTR-3B, because no invoice means no time of supply has been triggered. Table 5B of GSTR-9C exists specifically to add this figure back when reconciling GST turnover to audited turnover.

The number itself is informative. A founder tracking unbilled revenue as a rising percentage of monthly revenue, quarter over quarter, is watching the gap between “recognised” and “invoiced” widen. That gap is cash that has not yet become a receivable, let alone cash in the bank. It is also risk. If a client disputes the scope or the milestone, unbilled revenue can reverse a prior quarter’s booked profit with no corresponding GST credit note to soften the blow, because there was never an invoice to credit in the first place.

Reading the unbilled revenue trend

• Below 5 percent of monthly revenue, stable over three quarters: normal for a services business with a standard billing cycle
• Rising steadily as a percentage of revenue: a signal that invoicing is lagging delivery, which delays both cash collection and GST compliance timing
• Concentrated in two or three large clients: a concentration risk that a P&L alone will never surface, because the P&L shows one aggregate number
• Present in every month but never converting to an actual invoice within 60 to 90 days: a strong indicator that the revenue was recognised too early relative to the underlying contract terms

None of this shows up if a founder only reads the P&L. It shows up the moment someone builds the GSTR-9C Table 5 reconciliation properly and asks why the unbilled revenue line keeps growing rather than turning over.

Why related-party transactions surface in your GST data before anywhere else

If your company sells to, buys from, or transfers stock between related entities under common promoter control, GST law treats those transactions with a scrutiny your P&L was never designed to apply, and that scrutiny leaves a trail.

Under Schedule I of the CGST Act, 2017, certain transactions between related persons or between distinct persons (the same legal entity registered under different GSTINs in different states) are treated as a “supply” even without consideration, and are taxable. This includes stock transfers between your own branches in different states, and transactions between group companies under common control. Section 15(4) of the CGST Act, read with Rule 28 of the CGST Rules, requires such supplies to be valued at open market value, not at whatever internal transfer price the group has agreed for accounting convenience.

Your P&L, especially at the standalone entity level, may show related-party sales at cost-plus or at a negotiated internal rate with almost no margin, because the group’s tax and accounting teams have historically optimised for consolidated profit rather than GST valuation compliance. Your GST return, filed at the transaction level, has no such flexibility. Every inter-branch stock transfer and every related-party invoice sits in GSTR-1 at whatever value was actually charged, and an assessing officer comparing that value to comparable open-market transactions can reassess it under Rule 28.

This is one of the clearest examples of GST data revealing something the P&L structurally hides: a founder’s own group structure can be quietly under-pricing related-party transactions for years, showing healthy consolidated margins on paper, while the GST filings for each individual entity carry a valuation exposure that only becomes visible when someone actually pulls the GSTR-1 outward supply register and compares it, entity by entity, against arm’s length benchmarks.

This section covers domestic branch transfers and group-company transactions within India. Where the related party sits outside India, the same Rule 28 valuation question layers on top of income tax transfer pricing and FEMA remittance rules, which Treelife’s guide to intercompany service fees between Indian and foreign entities covers in full.

Is an ITC mismatch just a compliance problem, or a profitability signal?

An input tax credit (ITC) mismatch is usually treated as a filing headache to be cleared before the next return is due. Treated only that way, a founder misses that a persistent ITC mismatch is quietly inflating the company’s real cost of goods and services, because blocked or denied credit becomes a cost the P&L absorbs, often without anyone tagging it as a GST-driven loss.

When ITC claimed in GSTR-3B does not match the credit reflected in GSTR-2B (the auto-drafted statement based on supplier filings), the excess is liable to be reversed, typically with interest, and in persistent cases, through a voluntary payment via DRC-03. Every rupee of ITC that gets reversed because a vendor filed late, filed incorrectly, or under the wrong GSTIN is a rupee that should have reduced your cost of purchase, and instead sits as an unrecovered tax cost buried inside your expense lines.

A company with a wide vendor base can easily be carrying an ITC gap running into several lakhs, traced back to a handful of suppliers who filed with the wrong HSN code, the wrong GSTIN, or simply filed late enough that the credit never appeared in GSTR-2B for that period. That gap never appears in the P&L as a line item called “GST leakage.” It appears, if it appears at all, as a slightly higher cost of goods sold, unremarked and unexplained, unless someone runs the ITC reconciliation and traces it back.

What a growing ITC gap usually indicates

1. Vendor concentration risk: a handful of suppliers with poor GST compliance hygiene are quietly costing you working capital every month
2. Weak vendor onboarding controls: purchases are being made from unregistered or newly registered vendors without checking GST filing history
3. Internal booking errors: purchases recorded in the wrong month or against the wrong GSTIN for multi-state operations
4. Genuine ineligible credit: ITC claimed on blocked categories under Section 17(5) of the CGST Act, such as certain motor vehicles or employee welfare expenses, that should never have been claimed in the first place

A founder who only watches gross margin in the P&L will see margin compression and reach for pricing or vendor negotiation as the fix. A founder who reconciles ITC against GSTR-2B every month sees the actual mechanism, and can fix the vendor compliance problem instead of guessing at a pricing problem.

What credit note volume in your GSTR-1 reveals about real margins

A rising trend of credit notes issued in your GSTR-1, month over month, against a specific customer segment or product line, is one of the fastest ways to see where your booked revenue and your realised revenue are drifting apart, well before the annual audit catches it.

Every credit note issued under Section 34 of the CGST Act reduces both taxable value and tax liability for that supply, and must be reported in the corresponding GSTR-1. A pattern of frequent post-sale credit notes, whether for returns, price adjustments, discounts issued after invoicing, or disputed billing, is a direct, dated, transaction-level record of revenue that was originally booked at a higher value than what the company ultimately realised. The Finance Act, 2026 has made this easier to track from the seller’s side: Section 15(3)(b) of the CGST Act no longer requires a discount to be backed by a pre-supply agreement before it can reduce taxable value, so long as a credit note is issued under Section 34 and the recipient reverses the corresponding ITC. This means more post-sale discounts are likely to route through the credit note register going forward, which makes the register a more complete, not less reliable, source for tracking real realised margin.

Compare that pattern against your P&L, and the story often changes. A P&L shows net revenue after adjustments are booked, usually with a lag, sometimes bundled into a single “sales returns and allowances” line for the whole period. The GST data shows exactly which invoices were credited, when, and by how much, invoice by invoice. A founder who pulls this data by customer or by product line frequently discovers that one segment is generating a disproportionate share of credit notes relative to its revenue contribution, meaning the segment’s real margin is thinner than the headline P&L number suggests, because the P&L aggregates the adjustment rather than isolating it.

This matters directly for fundraising and for internal decision-making. An investor’s quality of earnings review will pull the credit note register as a matter of course. Finding it first, internally, on a monthly cadence rather than during diligence, is the difference between fixing a pricing or delivery problem quietly and explaining a revenue quality issue under time pressure during a raise.

Why is your GST turnover higher than your P&L turnover?

It usually means advances, deemed supplies, or non-GST income are being counted differently across the two systems, not that your GST filings are wrong. GSTR-9C Table 5 requires specific add-backs, including unadjusted advances, deemed supply under Schedule I, and trade discounts disallowed under GST, precisely because GST turnover and audited financial statement turnover are expected to differ by a reconcilable, documented amount.

The reconciliation format under Part A of GSTR-9C lays out the add-backs and deductions explicitly. Unbilled revenue at the start of the year and unadjusted advances at year end are added to audited turnover; unbilled revenue at year end and advances from the start of the year are deducted, along with turnover from periods outside the return period. Credit notes issued after year end but reflected in the annual return, and deemed supplies under Schedule I, both push GST turnover above what the books show for the same period.

Common reasons GST turnover exceeds book turnover

Reason	Why it happens	Where it shows up
Advances received near year end	GST is often payable on advances for goods and in specified reverse charge situations before revenue is recognised in books	GSTR-3B outward tax liability, no corresponding P&L entry
Deemed supply between GSTINs	Stock transfers between branches are taxable under Schedule I even with no consideration	GSTR-1 outward supply, eliminated on consolidation in books
Trade discounts disallowed under GST	The Finance Act, 2026 amended Section 15(3)(b) of the CGST Act to drop the old requirement that a discount be backed by a pre-supply agreement. A post-sale discount now only needs a credit note under Section 34 and a corresponding ITC reversal by the recipient. Discounts booked in the P&L without either of these two still cannot reduce GST taxable value	Higher taxable value in GST than net revenue in P&L
Export invoices under LUT	Recorded as taxable turnover in some GST tables even where zero-rated, depending on which GSTR-9C row is being checked	Reconciliation Table 7, not Table 5

None of this is inherently a problem. It becomes a problem when a founder cannot produce the explanation, or worse, has never looked closely enough to know one is needed. A GST officer scrutinising an assessment, or an investor’s CA reviewing revenue quality, will ask for exactly this breakdown. “The two numbers are close enough” is not an answer either audience accepts.

How investors and GST officers read the same GSTR-9C table differently

The same reconciliation table gets read for two very different purposes, and a founder who prepares it only for one audience is unprepared for the other.

A GST officer reviewing your GSTR-9C reconciliation during scrutiny or assessment is checking one thing: has the correct amount of GST been paid on time, on the correct taxable value, with legitimate ITC. Their concern stops at the tax liability. Timing differences, once explained with supporting documentation, are generally accepted, because Indian courts have repeatedly held that a mismatch alone, without evidence of unaccounted supply, does not establish tax evasion.

An investor’s CA, or your own board reviewing pre-raise diligence, is checking something different: whether the revenue in your P&L is real, recurring and collectible, and whether the gap between GST and book turnover hides a governance issue rather than a timing issue. Treelife’s own diligence experience shows this distinction plays out constantly. A SaaS company billing from a single GSTIN in Maharashtra with customers across five states will routinely show a gap between GSTR-1 and the audited P&L simply due to invoicing timing and state supply classification, and that gap needs a formal reconciliation note in the data room before the investor’s CA finds it, or it results in an escrow arrangement or a valuation reduction.

The practical implication is that a good reconciliation note does not just satisfy a compliance requirement. It pre-empts a valuation conversation. A founder who walks into diligence with a documented, three-year GST-to-P&L reconciliation converts what could have been a red flag into a five-minute confirmation. A founder without one hands the investor’s CA a reason to dig further, at exactly the point in the process where every extra week of scrutiny works against the founder’s negotiating position.

Common mistakes that cost founders time and money

Treating GST returns as a monthly filing task rather than a monthly financial control. Most finance teams file GSTR-1 and GSTR-3B on time and move on, without reconciling either return against the trial balance for that month. By the time GSTR-9 reconciliation happens, once a year, the explanations for a twelve-month gap have to be reconstructed from memory. Reconciling monthly, even briefly, converts a year-end forensic exercise into a five-minute check.

Booking related-party transactions at internal transfer price without a Rule 28 valuation defence. Groups that have operated for years with an internal pricing convention often have no contemporaneous documentation showing why that price approximates open market value. Under Rule 28 of the CGST Rules, the burden falls on the taxpayer to justify the valuation used. Without it, a GST assessment can reassess turnover retroactively across multiple years, each carrying interest and penalty exposure.

Ignoring ITC mismatches until the annual GSTR-9 exercise. ITC that fails to reconcile with GSTR-2B in month one, if left unresolved, compounds. Vendors who filed incorrectly in month one often repeat the error in months two and three, and by year end, the reversal along with interest under Section 50 of the CGST Act can run into lakhs for a mid-size company with a broad vendor base.

Assuming a GST turnover higher than book turnover always means an overpayment. Founders sometimes assume any excess is recoverable or a mere technical difference. Some of these differences, particularly deemed supply under Schedule I, represent genuine tax liability on transactions the P&L never captured at all, and cannot simply be reconciled away without paying the tax due.

Preparing the GSTR-9C reconciliation only in the last week before the deadline. GSTR-9C for FY 2025-26 is due 31 December 2026 for taxpayers with turnover above ₹5 crores. A reconciliation built under deadline pressure, without time to trace every unbilled revenue or advance line to source documents, produces a document that raises more questions than it answers if it is later pulled into an investor data room or a GST audit.

Treelife’s practitioner note

In the GST-to-P&L reconciliation engagements we have run at Treelife, the pattern that recurs most is not fraud, it is neglect. Founders are not hiding revenue. Their finance teams are simply filing GSTR-1 and GSTR-3B as a monthly task, closing the books as a separate monthly task, and never asking the two systems to agree with each other until an external party forces the question. We have seen companies discover, only during a Series B data room build, that a stock transfer between two GSTINs of the same entity had been treated as deemed supply under Schedule I for three years without anyone valuing it under Rule 28, creating a retrospective exposure the founders had no idea existed.

The specific pattern worth watching, one that rarely comes up outside live transaction work, is unbilled revenue that never converts. A services business can carry the same client’s unbilled revenue balance for four or five consecutive months, each month assuming the invoice will go out “next cycle.” When we trace that balance back to the underlying statement of work, we often find the deliverable was disputed or renegotiated months earlier, and the P&L has been carrying revenue that both the client and the company’s own delivery team no longer expect to invoice at the original value. The GST filings never show this, because no invoice was ever raised. Only a monthly reconciliation between the unbilled revenue schedule and the actual billing register catches it before the auditor does, at year end, as a sudden write-off.

Our approach is to build the GSTR-9C Table 5 reconciliation as a live, monthly working paper rather than a year-end exercise (Section 44, CGST Act 2017, and Rule 80(3), CGST Rules). Every unbilled revenue movement, every related-party transaction, and every credit note gets tagged and explained in the month it occurs. By the time the annual return is due, the explanation already exists, and by the time a fundraise or exit process begins, the founder has a defensible, dated record rather than a scramble.

Case study

Situation: A Series A B2B SaaS company based in Bengaluru, invoicing enterprise clients across four states from a single GSTIN, with revenue near ₹18 crores.

Challenge: The founder’s P&L showed 34 percent EBITDA margin, but the finance team had never reconciled GSTR-1 outward supply value against audited turnover. A pre-Series B due diligence request asked for a three-year GST-to-P&L reconciliation, which did not exist.

What Treelife did: Built the GSTR-9C Table 5 reconciliation for all three prior years, traced ₹2.1 crores of the gap to legitimate unbilled revenue and advance timing, and identified ₹34 lakhs of related-party stock transfer between two branch GSTINs that had never been valued under Rule 28.

Outcome: The valuation gap was regularised with a voluntary DRC-03 payment before the investor’s CA review began, avoiding an escrow clause the term sheet had flagged as a fallback, and the reconciliation note itself became a standing document in the data room for the remainder of the raise.

FAQ’s on what your GST returns reveal

Q: Why do GST returns and P&L never match exactly?
A: They follow different recognition rules. Revenue in your P&L follows accrual accounting under Ind AS or the applicable Accounting Standard, while GST liability follows the statutory time of supply under Sections 12 and 13 of the CGST Act, 2017. A reconciled, explained gap is normal. An unexplained one is not.

Q: How much advisory fee does a GST-to-P&L reconciliation typically cost?
A: Fees are usually structured per financial year reconciled, scaled by transaction volume and number of GSTINs, rather than as a flat fee. A single-entity, single-state company costs materially less to reconcile than a multi-state operation with several distinct-person transactions.

Q: How long does a full three-year GST-to-P&L reconciliation take?
A: For a mid-size company with clean books, four to six weeks is typical. Where unbilled revenue, related-party transactions, or ITC mismatches run across multiple years without prior documentation, it can extend to ten to twelve weeks, particularly if vendor-side GSTR-2B corrections are needed.

Q: What documents does a GST-to-P&L reconciliation require?
A: Audited financial statements, GSTR-1, GSTR-3B, and GSTR-2B for each year, the trial balance, the unbilled revenue and advance schedules, the related-party transaction register, and the credit note register from the accounting system.

Q: Does this reconciliation matter for companies with cross-border customers?
A: Yes. Export invoices under a Letter of Undertaking (LUT) are typically zero-rated but still need to be correctly classified in GSTR-1 and reconciled in GSTR-9C Table 7 against taxable turnover, since misclassification between exempt, zero-rated, and non-GST supply is one of the more common reconciliation errors in export-heavy businesses.

Q: How does GST reconciliation work when co-founders or family members hold related entities?
A: Any transaction between the company and an entity where co-founders or family members hold a controlling interest, or between two GSTINs of the same company, falls within the scope of Schedule I and Section 15(4) of the CGST Act, and needs an open market value defence under Rule 28, independent of how the transaction is priced internally for accounting purposes.

Q: Does DPIIT-recognised startup status change any of this?
A: No. DPIIT recognition affects income tax exemptions under Section 80-IAC (the term still in common use even after the Income Tax Act, 2025 came into force on 01/04/2026 and renumbered much of the statute). Angel tax under the old Section 56(2)(viib) was abolished with effect from 01/04/2025 and no longer applies to any DPIIT-recognised startup’s fresh fundraising round. None of this has any bearing on GST time of supply rules, related-party valuation under Rule 28, or the GSTR-9C reconciliation requirement.

Q: What happens if the GST-to-P&L gap is discovered during a term sheet process and not before?
A: Investors typically respond in one of two ways: an escrow holdback against the exposed amount, or a valuation adjustment to reflect the unresolved liability. Both slow the closing timeline. A reconciliation prepared and regularised before diligence begins avoids both outcomes.

Q: Are ESOP-related transactions relevant to this reconciliation?
A: ESOP exercise and allotment transactions are not typically GST-relevant, since they involve equity instruments rather than a supply of goods or services. They can, however, distort payroll cost comparisons between books and GST-relevant TDS filings if not clearly segregated in the accounting system.

Q: Can an ITC mismatch by itself trigger a GST notice?
A: Yes. A mismatch between ITC claimed in GSTR-3B and ITC reflected in GSTR-2B is one of the most common triggers for a show cause notice under Section 73 or Section 74 of the CGST Act, particularly where the mismatch persists across multiple return periods without correction.

Q: What is the buyer-side risk if my company’s GST filings are inconsistent with my P&L?
A: An acquirer’s diligence team treats an unreconciled gap as an unquantified liability. Depending on materiality, this can result in a purchase price holdback, an indemnity clause specific to GST exposure, or, in smaller deals, a straightforward reduction in the agreed consideration.

Q: Does a promoter’s personal GST registration affect the company’s reconciliation?
A: If a promoter holds a separate GST registration for another business and that entity transacts with the company, those transactions fall under the related-party and distinct-person rules discussed above, and must be reconciled and valued exactly as any other related-party transaction would be.

Q: How often should a growing company run this reconciliation, rather than waiting for the annual GSTR-9C?
A: Monthly, as part of the standard month-end close, is the practice Treelife recommends for any company above ₹10 crores in annual turnover or with multiple GSTINs. Waiting for the annual exercise concentrates twelve months of potential discrepancies into a single, high-pressure reconciliation window.

Regulatory references

• Sections 12 and 13, Central Goods and Services Tax (CGST) Act, 2017, time of supply for goods and services
• Section 15(4), CGST Act, 2017, and Rule 28, CGST Rules, 2017, valuation of supply between related persons and distinct persons
• Schedule I, CGST Act, 2017, activities treated as supply without consideration
• Section 34, CGST Act, 2017, credit and debit notes, read with Section 15(3)(b) as amended by the Finance Act, 2026, which removed the pre-agreement requirement for post-sale discounts
• Section 17(5), CGST Act, 2017, blocked input tax credit
• Sections 44 and 50, CGST Act, 2017, and Rule 80(3), CGST Rules, 2017, annual return, reconciliation statement (GSTR-9C), and interest on delayed payment
• Sections 73 and 74, CGST Act, 2017, determination of tax not paid or short paid

External sources

• Goods and Services Tax Network (GST portal)
• Central Board of Indirect Taxes and Customs (CBIC)
• Income Tax India
• Ministry of Corporate Affairs