Sales tax collected vs revenue reported: a quick diligence test

When you’re evaluating a small acquisition, the gap between what a seller reports as revenue and what they’ve actually collected in sales tax can expose hidden liabilities or revenue quality issues faster than almost any other single metric. This discrepancy—sometimes legitimate, sometimes not—sits at the intersection of tax compliance and cash collection reality. Most buyers and their advisors check the numbers, but they don’t always check them against each other. That mismatch can cost you six figures in unexpected tax exposure, particularly in product-based or multi-state businesses where sales tax obligations pile up quickly.

Why Sales Tax and Revenue Don’t Always Track

Revenue on a P&L and sales tax collected are measuring different things, which is why they can diverge. Revenue is recognized when earned (accrual basis), while sales tax collected reflects only taxable sales actually made and documented. In a clean scenario, they move together. In reality, several common scenarios create friction:

• Exemptions and exclusions: Services, labor, resale certificates, and interstate sales may be exempt. A software company billing $500K annually might collect tax on only $50K of SaaS implementation fees while the rest sits untaxed.
• Timing gaps: A seller might recognize revenue in November but not file or remit sales tax until January. Monthly P&L looks strong; tax liability is hidden in payables.
• Unremitted tax: The business collected tax at point of sale, recorded it as revenue, spent it, and never remitted it to the state. This is a balance sheet liability that walks into your acquisition.
• Multi-state complications: A business shipping nationwide may have collected sales tax in only a few states, but tax authorities in states where they’ve crossed the economic nexus threshold are now owed back taxes plus penalties.

The Reconciliation Method: A Practical Walkthrough

Start with last 12–24 months of filed sales tax returns. Line these up against gross revenue reported in the same periods on the P&L. A mismatch doesn’t scream fraud—it tells you where to dig.

Step 1: Calculate taxable sales from filed returns. Take the sales tax reported on each filed return and divide by the jurisdiction’s tax rate. If a seller filed $15,000 in sales tax in State A (7% rate), their documented taxable sales for that period were roughly $214,000.

Step 2: Compare to P&L revenue for the same periods. If the P&L shows $850,000 gross revenue but sales tax returns show only $214,000 in taxable sales across all jurisdictions, ask why 75% of revenue generated no tax obligation. Legitimate answers include: strong service component, high resale volume, drop-shipping arrangements, or genuine exemptions. Dodgy answers include: no sales tax filing in certain states, or revenue that was never actually collected.

Step 3: Audit the payables schedule. Pull the balance sheet detail for sales tax payable, accrued taxes, and any deferred tax liability line items. A seller who shows $0 in sales tax payable but filed returns claiming tax collected is a red flag—money came in, tax wasn’t set aside, and now you own the liability.

Step 4: Check nexus and compliance timeline. Request a summary of which states the business filed sales tax returns in over the past three years. Cross-reference this against where the seller actually ships or sells. If they have customers in California but filed zero sales tax there until last quarter, there’s unremitted tax sitting in someone’s records (likely a state auditor’s desk). Penalties start accruing the moment a filing deadline passes.

A Concrete Example: E-Commerce Reseller

Imagine a B2B parts reseller doing $2.2M in annual revenue. They hold inventory, sell to licensed resellers (exempt) and direct to end-users (taxable). On their P&L: $2.2M revenue. On their sales tax returns filed in three states: $180K in sales tax collected ($180K ÷ various rates = roughly $850K in documented taxable sales). The gap: $1.35M unaccounted for. In conversation, the owner explains: 60% of revenue is resale to exempt customers (legitimate), 10% is shipped to states where they only recently registered (unremitted tax liability), and 30% is direct sales they did file tax on. That 10%—roughly $220K in revenue—may carry $15–20K in unremitted tax plus penalties. Without the reconciliation, you’d discover this in an audit notice 18 months post-close.

Red Flags That Warrant Deeper Diligence

• Revenue exceeds taxable sales by over 40% without a clear, documented explanation (e.g., audited service revenue ratio or certified exempt resale certificates on file).
• Filed returns show gaps. Returns filed only in one state for a nationally shipping business, or abrupt start dates with no back-filing history.
• Sales tax payable is negative or suspiciously low. A $2M annual revenue business should carry at least 2–3 months of payable liability on the balance sheet.
• Variance month-to-month without seasonal explanation. If June has 8% of annual revenue but only 0.5% of annual tax filed, something’s inconsistent.
• No nexus study or multi-state analysis on file. If the owner can’t produce a document showing which states they’re obligated to file in, assume they haven’t.

How This Fits Into Deal Economics

Sales tax exposure directly impacts working capital adjustments and post-close escrow. If you discover $30K in unremitted sales tax during diligence, that comes off the purchase price or into an escrow hold—either way, it’s real cost to the buyer. Worse, if you miss it and close, you inherit the liability plus state penalties and interest, which can compound to 150–200% of the original amount within two years.

During normalized earnings calculation, unremitted sales tax should never be treated as an add-back (it’s not a discretionary cost—it’s owed money). Sellers sometimes try to flag it as such. A normalized EBITDA calculation that includes sales tax liability disguises the true cash position and understates the buyer’s real net cash outlay at close.

Documentation Checklist for Your Review

• 12–24 months of filed sales tax returns (all jurisdictions).
• General ledger detail for sales tax payable, accrued taxes, and revenue recognition by category (product vs. service vs. resale).
• Proof of sales tax registration in each state where revenue was generated.
• Any correspondence with state tax authorities, audits, or assessments (even if resolved).
• Summary of exempt customer base with documentation (resale certificates, 501(c)(3) letters, etc.) and estimated % of total revenue.

Frequently Asked Questions

Can a business legitimately have revenue without corresponding sales tax obligations?

Yes. Service businesses, businesses with substantial resale customers (who hold valid resale certificates), and interstate sales into states without nexus generate revenue without sales tax. The key is documentation: you need resale certificates on file, service contracts segregated on the P&L, or proof the seller checked nexus thresholds. Without that paper trail, it looks like evasion or poor bookkeeping, both of which add diligence cost.

What counts as unremitted sales tax liability I should account for in working capital?

Any sales tax collected (or that should have been collected) and not yet paid to a tax jurisdiction. This includes returns filed but unpaid, returns not yet filed despite collection, and tax owed for periods where no return was filed at all. Your working capital peg should reserve enough cash to cover the maximum probable amount, then treat any difference as a seller holdback in escrow until the liability is resolved.

How do I know if the seller had nexus in a state they didn’t file in?

Review customer shipping addresses, credit card processor statements showing transaction locations, and any registered business addresses or employees in that state. If the P&L shows revenue categorized by customer or region, use that. Many small sellers also file a Form SS-4 (EIN application) in each state where they operate; request a copy. If revenue clearly points to a state but no return was ever filed, assume nexus was triggered and ask the seller to quantify the exposure.

Is sales tax an add-back for normalized EBITDA calculations?

No. Sales tax is a legal obligation, not a discretionary owner expense. If it’s unpaid, it’s a liability you’re assuming at close. If it was paid, it’s a legitimate cost that reduces EBITDA. Some sellers attempt to flag it as an add-back; resist that framing. The only exception: if the seller can prove they overpaid in a prior year and are expecting a refund, the refund amount might warrant adjustment—but only if the refund is documented and collectible by the buyer post-close.

What’s the difference between sales tax liability found in diligence and a traditional sales tax audit?

Diligence uncovers what the seller’s records show (or don’t show). An audit by a state revenue agent is a formal examination that produces an assessment, interest, and penalties. If your diligence finds gaps, you’re identifying risk before the state does. Once an audit notice arrives, the seller often can’t dispute the assessment, and the new owner is liable. Finding and quantifying the exposure yourself gives you negotiating power; letting it surprise you post-close is expensive.

Bringing It Together

The sales tax–to-revenue reconciliation is one of the fastest reality checks in small acquisition diligence. It takes a few hours and a basic calculator, and it catches problems that balance sheet scrutiny alone often misses. A clean story—revenue, taxable sales, and filed returns all align with documented exemptions for the gap—gives you confidence. A messy story demands escrow protection and a post-close adjustment. Either way, you’ll know before you sign.

This article is educational and does not constitute M&A, investment, or accounting advice — confirm findings with a licensed CPA or M&A advisor before making an offer.

This article is educational and does not constitute M&A, investment, or accounting advice — confirm findings with a licensed CPA or M&A advisor before making an offer.

See how IncomeReady organizes normalized EBITDA and SDE before you make an offer.