The LOI is signed. The quality of earnings report is underway. Your deal team is deep in financial diligence, reviewing customer concentration, working capital adjustments, and EBITDA normalization. And nobody has said the words “sales tax” yet.
That’s the problem.
Sales tax is one of the most common material liabilities uncovered during M&A diligence. It’s also one of the most consistently overlooked until it’s too late to address cleanly. Unlike income tax, sales tax exposure rarely shows up on a balance sheet. It hides in unregistered states, unfiled returns, and years of mistreated taxability for SaaS, digital goods, or services that crossed state lines without anyone asking the compliance question.
Buyers often set aside 2 to 12 percent of purchase price for potential tax liabilities. Sales tax exposure alone can represent up to 10 percent of a target company’s revenue when penalties and interest are factored in. That’s not a rounding error. That’s a material number that changes deal economics.
This article explains exactly how sales tax liability works in a transaction, what to look for during diligence, and what your options are before and after close. Whether you’re evaluating an asset purchase or stepping into a stock deal, you’ll walk away knowing where the risks live and how to address them before they become your problem.
Sales Tax Is the Liability Nobody Sees Coming
Here’s what makes sales tax different from almost every other liability on your diligence checklist: it’s self-assessed and self-reported. If a company never registered in a state, there’s no notice, no filing history, and no line item on the balance sheet. The liability is invisible until someone goes looking.
And when someone does go looking, the numbers can be significant.
Private companies are especially prone to hidden exposure. Growth-stage businesses tend to prioritize revenue over compliance infrastructure. That’s not negligent. It’s a rational business decision when you’re trying to hit milestones and close funding rounds. But it means that by the time a company becomes an acquisition target, there may be years of unaddressed nexus obligations sitting quietly in the background.
The 2018 South Dakota v. Wayfair decision made this worse. Before Wayfair, companies generally only had sales tax obligations in states where they had a physical presence. After Wayfair, any company selling across state lines likely has economic nexus obligations in multiple states based purely on sales volume or transaction count. A SaaS company with customers in 30 states may have nexus in 20 or more of them, even if every employee works from a single office.
The exposure isn’t just the uncollected tax. It’s tax plus penalties plus interest. Depending on the state and how long the liability has been accruing, penalties and interest can add 25 to 50 percent on top of the base tax owed. A $500,000 exposure becomes $750,000 fast.
Certain industries carry higher risk than others:
- SaaS and software companies: As of 2026, 24-25 states tax SaaS in some form. The rules vary wildly. Some states tax it as tangible personal property, others as a service, and some don’t tax it at all. Companies that assumed “software isn’t taxable” often have multi-state exposure they’ve never addressed.
- E-commerce businesses: High transaction volumes across many states create economic nexus quickly. Marketplace facilitator laws have shifted some liability, but not all of it.
- Services companies that expanded multi-state: Professional services, consulting, and B2B services have complex taxability rules that differ by state. A company that started in one state and grew nationally may have never reassessed its obligations.
- Companies that changed ownership or product mix: Any business that pivoted, added product lines, or went through a prior transaction may have taxability configurations that no longer match what they actually sell.
When acquirers’ advisors start pulling data, these gaps surface quickly. The question isn’t whether there’s exposure. The question is how much, and who’s going to pay for it.
How You Structure the Deal Determines Who Inherits the Problem
The single most consequential sales tax decision in an M&A transaction often happens before diligence even begins: how is the deal structured?
Asset purchase versus stock purchase determines not just the tax treatment of the transaction itself, but how much historical sales tax liability the buyer is exposed to. Get this wrong, and you may be inheriting years of someone else’s compliance failures.
| Asset Purchase | Stock/Equity Purchase | |
| What transfers | Selected assets only; legal entity stays with seller | Entire entity, including all assets and liabilities |
| Successor liability exposure | Lower (but not eliminated) | High: buyer steps into the seller’s legal shoes |
| Historical sales tax risk | Buyer generally not responsible for pre-close liabilities, unless bulk sale rules apply, a de facto merger is found, or exceptions trigger | Buyer inherits all pre-close liabilities by default |
| Transaction itself taxable? | Often yes: transfer of tangible property may be subject to sales tax (varies by state; many have “occasional sale” exemptions) | Generally not a taxable event for sales tax purposes |
| Key watch-out | Bulk sale notification requirements in many states (NY, CA, IL, others): failure can result in buyer liability for seller’s unpaid taxes | Any undisclosed nexus, unfiled returns, or audit history becomes the buyer’s problem at close |
Even an asset purchase doesn’t fully insulate a buyer. Many states have statutory successor liability provisions that impose liability regardless of deal structure, particularly when bulk sale clearance certificates are not obtained.
New York is a good example. The state explicitly warns buyers not to pay the seller until confirming there are no outstanding tax obligations. If you skip the clearance certificate and the seller had unpaid sales tax, you’re on the hook. California, Illinois, and several other states have similar provisions.
Successor liability (the legal principle that makes a buyer responsible for a seller’s obligations) can attach in asset deals when:
- Bulk sale notification requirements aren’t followed
- The buyer continues the seller’s business without meaningful change
- Courts find a “de facto merger” based on continuity of operations, management, or ownership
- The transaction is structured to avoid creditors
The takeaway: deal structure matters, but it’s not a complete shield. You still need to know what you’re buying.
What Good Diligence Covers (And What Most Teams Skip)
Most deal teams outsource tax diligence to generalist advisors who know income tax well but may not go deep on state and local tax. Sales tax gets a cursory review, if it gets reviewed at all. That’s how material liabilities slip through.
A proper sales tax diligence review examines six areas:
Nexus footprint: Where does the target have economic or physical nexus? Where are they registered versus where they should be registered? The gap between those two lists is your exposure. You can use a nexus calculator to get a preliminary read, but a full nexus study requires transaction-level data analysis.
Return history: Are returns filed in all registered states? Any gaps, amended returns, or notices outstanding? A company that’s registered but hasn’t filed in 18 months has a different problem than a company that never registered at all.
Taxability analysis: Are the right products and services being taxed? This is especially critical for mixed transactions, SaaS, digital goods, or professional services. A company might be collecting tax on some products but not others, or applying the wrong rate, or treating bundled offerings incorrectly. Taxability errors create both over-collection risk (customer refund liability) and under-collection risk (state liability).
Exemption certificates: Does the company have valid, current exemption documentation on file for exempt sales? Missing certificates are one of the most common audit triggers. If 30 percent of a company’s sales are marked as exempt but only half have documentation, that’s a quantifiable exposure.
Audit history: Any open audits, state notices, or assessments? These survive a deal. If the target is in the middle of a California audit, that audit continues after close regardless of deal structure.
Use tax compliance: Many companies are diligent on sales tax but ignore use tax on their own purchases. Use tax applies when a company buys goods or services without paying sales tax and owes the tax directly to the state. Auditors always check both sides.
The output of this review is a quantified exposure estimate. Not a vague “there might be risk” statement, but an actual number the deal team can work with when structuring indemnifications, escrow, or purchase price adjustments.
We’ve worked on transactions where this review identified over $500,000 in exposure that wasn’t on anyone’s radar. That’s not unusual. It’s what happens when you actually look.
Once You Find the Exposure, Here’s What You Can Actually Do About It
Finding sales tax exposure before a deal closes is infinitely better than finding it after. Before close, you have leverage. You have options. You can negotiate who absorbs the liability and how. After close, it’s your problem.
Here’s the menu of options.
Price Adjustment and Indemnification
The most common path. Buyer and seller negotiate who absorbs the liability, typically via an indemnification clause in the purchase agreement with escrow funds held for a defined period.
A common escrow structure is 135 percent of estimated exposure, held for 18 to 24 months. The cushion accounts for uncertainty in the estimate and gives time for VDA resolutions or audits to play out.
Indemnification language matters. You want clear definitions of what constitutes a pre-close liability, how claims are made, and what happens if the escrow runs out before all liabilities are resolved.
Voluntary Disclosure Agreements (VDAs)
A VDA allows a company to come forward voluntarily in each state with exposure, pay back taxes and interest, and in most cases get penalties fully waived and the look-back period limited to three to four years (versus potentially unlimited for non-filers).
VDAs can often be negotiated anonymously before the company’s identity is disclosed. This matters because once a state knows who you are, you lose the ability to control timing.
Informed buyers often negotiate the right to file VDAs post-close with the seller funding the pre-close portion of the liability. This gives the buyer control over the process while allocating costs appropriately.
VDAs are one of the most effective tools for cleaning up historical exposure. If you’re evaluating a target with multi-state nexus issues, this is likely part of your remediation plan. Learn more about how registrations and VDAs work in practice.
Bulk Sale Clearance Certificates
In states that require them, getting a clearance certificate from the tax authority before transferring assets confirms the seller has no outstanding tax obligations. Skipping this step can make the buyer liable for the seller’s unpaid taxes.
The process takes time. Some states respond in days, others take weeks. Build this into your closing timeline.
Tax Escrow
Funds held in escrow post-close to cover liability that gets confirmed through VDA resolution or audit. This is standard in PE-backed deals where the exposure is material but not fully quantified.
The escrow amount, release conditions, and duration should all be negotiated based on the specific exposure identified during diligence.
Post-Close Integration Priorities (First 90 to 100 Days)
Once the deal closes, the clock starts on integration. Sales tax shouldn’t be an afterthought.
Re-register the acquired entity in all required jurisdictions under the new ownership. State requirements vary on whether this is a simple update or a new registration.
Consolidate exemption certificate systems and validate that existing certificates are current. Acquired companies often have certificates scattered across email folders, filing cabinets, and outdated systems.
Audit the acquired company’s taxability setup in its ERP or billing system. This is a common place where miscoding survives an acquisition. If the system is configured to not charge tax on a product that should be taxed, that error will continue generating liability until someone fixes it.
Assess combined entity nexus. The buyer’s existing operations may now create additional nexus for the acquired entity, and vice versa. A buyer with employees in 15 states may create physical nexus for an acquired company that previously only had economic nexus in five.
File any agreed-upon VDAs if they were negotiated as a pre-close condition.
For a broader view of compliance fundamentals, especially if the target is an earlier-stage company, our sales tax checklist for startups covers the baseline requirements that should already be in place.
Sales Tax M&A Checklist: What to Cover Before You Close
This checklist covers the essential steps at each phase of a transaction. Use it as a reference for your deal team.
Pre-LOI and Early Diligence
- Request the target’s state registration list and compare to states where they have nexus
- Ask for the last three years of sales tax returns by state
- Flag any states where the target sells but is not registered
- Identify the deal structure (asset vs. stock) and its successor liability implications
During Diligence
- Commission a full nexus study for the target entity
- Review exemption certificate files for completeness and currency
- Pull audit history and any outstanding state notices or assessments
- Assess taxability treatment for all product and service lines, especially digital, SaaS, or services
- Quantify prior-period exposure with penalties and interest included
- Identify bulk sale notification requirements in applicable states
Pre-Close
- Negotiate indemnification language in the purchase agreement for pre-close liabilities
- Determine whether VDAs should be filed pre-close or negotiated as a post-close right
- Obtain bulk sale clearance certificates where required
- Establish escrow structure if exposure is material
Post-Close (First 90 to 100 Days)
- Re-register or transfer tax accounts in all required jurisdictions
- Integrate acquired entity into buyer’s compliance calendar and filing process
- Validate and update taxability configuration in billing and ERP systems
- File any agreed VDAs
- Assess combined entity nexus footprint, as new obligations may exist that didn’t before the deal
The Best Time to Deal With Sales Tax Is Before the Deal Is Done
Most deals where sales tax becomes a problem aren’t the result of negligence. Sales tax compliance is genuinely complex, self-assessed, and easy to deprioritize during a growth phase. When you’re focused on hitting revenue targets and building a business, nexus analysis doesn’t make the weekly priority list. The issue is that M&A is the moment all of that catches up.
A specialized sales tax review during diligence doesn’t add complexity to the deal. It removes it. You go into negotiations knowing the actual number, with a plan to address it, rather than discovering exposure at a closing table or, worse, in an audit 18 months post-close when the seller is long gone and the escrow has been released.
The math is straightforward. A thorough diligence review costs a fraction of what unidentified exposure costs when it surfaces later. We’ve worked on deals ranging from founder exits to large strategic acquisitions, including transactions like the $1.65 billion Acima acquisition by Rent-A-Center, where identifying and resolving sales tax exposure early kept it from becoming a deal issue or a post-close liability.
If you’re in or approaching a transaction, the due diligence review starts with a conversation. No fees, no pressure. Just a clear picture of where you stand and what your options are. Schedule a What’s Next call with our team to talk through your specific situation and get a roadmap for protecting your deal.
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