Sales Tax Notice From a State? What to Do Before You Respond

October 7, 2026

Sales Tax Notice From a State? What to Do Before You Respond

Receiving a sales tax notice from a state can create an immediate urge to answer the letter, pay the amount shown, register the business, or call the person listed on the notice.

That is not always the best first move.

A sales tax notice can mean many different things. A state may be asking for a missing return, questioning whether your business has nexus, proposing an audit adjustment, assessing unpaid tax, requesting records, or notifying you of formal protest rights. The correct response depends on exactly what the state has sent, which periods are involved, what your business actually did in the state, and whether the notice carries a statutory deadline.

For ecommerce businesses, Amazon and Shopify sellers, SaaS companies, multistate businesses, founders and finance teams, one poorly considered response can also raise issues beyond the single letter.

This guide explains how to identify the notice, protect your response deadline, investigate the facts, gather the right records and determine the appropriate next step before communicating your position to the state.

Key Takeaways

Do not ignore a sales tax notice, even if you believe the state made a mistake. Streamlined Sales Tax specifically advises businesses to contact the state promptly if they do not understand a notice.
Do not assume every sales tax notice is an assessment. Some notices request information, identify filing gaps or begin a nexus or audit inquiry.
Identify the notice date, response deadline, tax type, periods covered, legal entity and amount at issue before doing anything else.
Response and appeal deadlines are state-specific. California, Texas, Washington, Illinois and New York illustrate materially different procedures.
Verify that the notice is genuine through an independently obtained state contact or official portal, especially before submitting sensitive information or payment.
Reconcile the state’s position against your returns, payments, sales data, marketplace activity, exemption documentation and nexus history.
A nexus inquiry may affect voluntary disclosure options. Under the Multistate Tax Commission program, prior contact regarding the tax type can make a taxpayer ineligible for voluntary disclosure.
If the notice involves significant historical exposure, multiple states, an audit assessment, responsible-person liability or a short protest deadline, professional review should occur before a substantive response is submitted.

What Is a Sales Tax Notice?

Definition snippet: A sales tax notice is an official communication from a state or other taxing authority concerning a business’s sales or use tax account, filing history, registration status, nexus, reported transactions, audit findings or unpaid liability. The notice may request information, require corrective action or provide formal rights to dispute an assessment.

Not every notice means that the state has concluded you owe tax.

That distinction matters.

A letter asking why your business made sales into a state without registering is different from a notice stating that an assessment has already been issued. A missing-return notice is different from an audit information request. A notice carrying formal protest rights is different from correspondence that can still be resolved administratively through account documentation.

The first question should therefore be:

What exactly did the state send?

Why Do Businesses Receive State Sales Tax Notices?

State notices generally arise because something in the state’s records requires clarification, correction, payment or further investigation.

Common situations include:

Notice issue	What may be happening	First issue to investigate
Missing return	State expected a return but did not receive one	Was the business registered and required to file that period?
Payment discrepancy	Return and payment records do not reconcile	Was payment made, posted correctly or applied to another period?
Nexus inquiry	State is examining whether registration should have occurred	When did physical or economic nexus arise?
Audit notice	State has opened an examination	Which periods, entities and tax types are included?
Proposed assessment	State believes additional tax is due	What transactions or assumptions produced the assessment?
Exemption issue	State questions untaxed transactions	Are valid exemption or resale certificates available?
Filing-frequency issue	State expected returns on another schedule	Was filing frequency changed or misunderstood?
Registration issue	State believes a permit or account is required	Does the business actually have nexus and taxable activity?

Businesses already registered with a state may be required to continue filing for assigned reporting periods even when no tax is due. Streamlined Sales Tax notes that states generally expect registered sellers to file each required reporting period unless the state has established another filing arrangement.

For a deeper explanation of filing schedules, see MSTF’s Sales Tax Filing Frequency: Monthly vs Quarterly vs Annual guide.

What Should You Do First After Receiving a Sales Tax Notice?

The safest approach is structured triage rather than an immediate substantive reply.

1. Preserve the complete notice

Save every page, attachment and envelope. If the notice appeared in a state portal, download a complete copy.

Record:

notice number
account number
legal entity
tax type
notice date
periods involved
claimed amount
response deadline
appeal or protest deadline
state contact information
instructions for submitting a response

Do not rely on someone’s memory of what the letter said.

2. Calendar the deadline immediately

The deadline should be treated separately from the investigation.

You may still be determining whether the state is correct when a filing deadline arrives. Protecting procedural rights can therefore become more urgent than completing the substantive analysis.

3. Verify the notice

Tax-related impersonation attempts exist. New York warns that scammers may use letters, calls, emails and texts that appear to originate from a tax agency. Texas likewise advises taxpayers receiving suspicious communications to verify an inquiry through independently obtained Comptroller contact information.

Do not verify a suspicious notice solely by calling the phone number printed on it. Use the state’s official website or your existing taxpayer portal.

4. Identify the notice type

A notice requesting information should not automatically be handled like a final assessment.

Similarly, a tax bill should not automatically be treated as correct simply because a state computer generated it.

Classifying the notice determines everything that follows.

How Long Do You Have to Respond to a Sales Tax Notice?

There is no single nationwide sales tax notice deadline.

Deadlines vary by state, notice type, stage of the audit or assessment process and sometimes the method by which the notice was issued.

Consider these current examples:

State	Notice or proceeding	Current procedural example
California	Notice of Determination	A petition for redetermination generally must be filed within 30 days from the date the notice was mailed.
Texas	Notice of Tax Due after an audit	The Comptroller’s audit guidance states that a taxpayer normally has 30 days after receiving the notice to request a redetermination hearing. Different rules can apply to jeopardy determinations.
Washington	Assessment review	A written review request and supporting documents, or an extension request, generally must be submitted within 30 days of the assessment date.
Illinois	Certain deficiency, assessment and claim-denial notices with protest rights	IDOR generally provides 60 days to request an administrative hearing or petition the Independent Tax Tribunal, with a different period for IFTA matters.
New York	Department notice carrying protest rights	The applicable statutory period appears on the notice. New York warns that later correspondence with the Department does not extend a formal protest deadline.

The practical rule is simple:

Read the deadline printed on the actual notice and verify it against the official procedure for that specific notice type.

For California, see the CDTFA Appeals Procedures publication. For Texas, review the Texas Comptroller audit and redetermination guidance. Washington taxpayers can consult the state’s excise tax review procedure.

What Records Should You Gather Before Responding?

Once the notice is classified, build a record set around the issue it raises.

Depending on the notice, relevant documents may include:

Sales tax returns for the periods involved.
Payment confirmations.
State account transcripts or filing histories.
General ledger data.
Sales-by-state reports.
Customer invoices.
Marketplace sales reports.
Shopify or other direct-channel transaction exports.
Exemption and resale certificates.
Credit memos and returns.
Product taxability documentation.
Registration records.
Prior state correspondence.
Nexus analyses.
Shipping and fulfillment records.

The point is not to send all of these records to the state automatically.

The point is to determine which records prove or disprove the state’s position.

If the issue involves exempt sales, MSTF’s Sales Tax Exemption Certificates Explained guide provides additional background on certificate documentation.

What If the State Says You Should Have Registered for Sales Tax?

A nexus or registration notice requires more analysis than simply asking whether your business has customers in the state.

You need to establish when the obligation may have started.

Review:

physical presence
employees or representatives
offices or locations
inventory or fulfillment activity
direct sales
marketplace sales
the state’s economic nexus measurement rules
the applicable measurement period
the taxability of what you sell
any prior registration or filing history

Do not assume that marketplace collection resolves every issue.

A business selling through Amazon, Walmart or another marketplace may also have direct Shopify, SaaS, wholesale or other sales that require separate analysis.

Likewise, economic nexus thresholds and what counts toward them are not uniform. Use MSTF’s 2026 Economic Nexus Thresholds by State guide as a starting point, then verify the state rule applicable to your facts.

If registration is actually required, MSTF also maintains a state sales tax registration guide.

What If the Notice Says You Failed to File a Return?

Start by determining whether the return was actually required.

If the business was registered during the period, the answer may be yes even when no tax was due. Streamlined Sales Tax specifically notes that states generally expect registered sellers to file for their assigned periods, including periods with no tax to report unless another filing status applies.

Then determine whether:

the return was filed but posted incorrectly,
the return was rejected,
the business closed the account,
filing frequency changed,
a zero return was missed,
another tax account was used,
payment was made without a corresponding accepted return.

Do not file duplicate returns merely because a notice says something is missing. Confirm the account history first.

What If the Notice Is an Audit or Proposed Assessment?

The stakes change once the state has moved from asking questions to formally examining or assessing the business.

An audit assessment may involve:

unreported taxable sales,
tax collected but not remitted,
unsupported exempt sales,
use tax,
taxability classifications,
sampling or projection,
registration periods,
penalties,
interest.

Review the auditor’s schedules and assumptions line by line.

The Multistate Tax Commission’s joint sales tax audit process illustrates the broader sequence: auditors obtain records, develop proposed adjustments, allow taxpayer review, complete state audit findings and then individual states issue assessments. Taxpayers may then protest the state results under the relevant state’s procedure.

MSTF’s Sales Tax Audit Process guide explains the audit cycle in greater detail.

Why Ecommerce and Multichannel Businesses Need a Reconciliation Before Responding

For ecommerce businesses, the number printed on a notice may not tell you why the state reached that number.

Suppose the business sells through:

Amazon Marketplace,
a Shopify website,
Walmart Marketplace,
wholesale channels,
direct invoices.

The first reconciliation should separate marketplace transactions from direct transactions.

That matters because a marketplace facilitator may collect and remit tax on facilitated transactions while the seller remains responsible for other activity.

The analysis should answer:

What were total destination-state sales?
Which sales occurred through marketplaces?
Which sales occurred directly?
What amounts did marketplace facilitators collect?
What direct sales were taxable?
What direct sales were exempt?
What tax did the seller collect?
What tax did the seller actually remit?
What returns were filed?
Do return totals reconcile to the underlying transaction data?

This is often more useful than drafting a narrative reply first.

Facts should drive the response.

Can a State Notice Affect Voluntary Disclosure Options?

Yes, potentially.

This is one reason businesses should not treat a nexus notice as routine correspondence.

The Multistate Tax Commission’s Multistate Voluntary Disclosure Program states that prior state contact concerning the relevant tax type can disqualify a taxpayer from voluntary disclosure through that program. MTC specifically identifies receiving an inquiry from the state as a form of prior contact.

That does not mean every state applies identical VDA eligibility rules.

It means that timing matters.

If your notice reveals broader historical exposure in other states that have not contacted the business, those states should be reviewed separately before registrations or unsolicited filings are made.

For more detail, see MSTF’s 2026 Voluntary Disclosure Agreement guide.

How Should a Sales Tax Notice Response Be Built?

A strong response is usually factual, organized and limited to the issue actually raised.

Depending on the notice, a response may include:

taxpayer identification,
notice number,
tax period,
statement of the issue,
relevant facts,
explanation of the taxpayer’s position,
reconciliation schedule,
supporting documents,
proof of prior filing or payment,
exemption documentation,
legal or administrative authority where relevant,
specific requested resolution.

Avoid flooding the state with unrelated records.

The response should make it easy for the reviewer to answer one question:

What evidence shows how this notice should be resolved?

If the issue is technical, the legal analysis should be tied to the specific state statute, regulation, administrative guidance or controlling authority.

Hypothetical Example 1: Shopify Seller Receives a Nexus Questionnaire

Business situation: A Colorado-based ecommerce seller operates a Shopify store and ships products nationwide. It receives a nexus questionnaire from another state where it has never registered.

Tax issue: The state wants information about the seller’s activity and whether a registration obligation arose.

What the business should determine: The company should calculate state sales for the relevant measurement periods, identify any physical presence, analyze taxable versus exempt sales and determine whether marketplace transactions are involved.

Action: Preserve the notice deadline, establish the nexus timeline, then respond accurately to the questions asked.

Why this matters: Registering immediately without understanding the historical period does not automatically resolve prior exposure. Ignoring the questionnaire can also allow the matter to escalate.

Hypothetical Example 2: Amazon and Direct Sales Do Not Match the State’s Estimate

Business situation: A company sells primarily through Amazon but also operates its own direct website. A state issues an assessment based on total state sales.

Tax issue: The assessment may not distinguish between marketplace transactions and direct transactions.

What the business should determine: Reconcile Amazon sales, marketplace-collected tax, direct website sales, exempt transactions and filed returns.

Action: Build a transaction-level reconciliation and compare it with the assessment methodology before determining whether to protest.

Risk if ignored: An estimated assessment may become final if the business fails to exercise available protest rights within the applicable deadline.

Hypothetical Example 3: Missing Return Notice After an Account Change

Business situation: A company receives a notice stating that a quarterly return was not filed. The finance team believes the return was submitted.

Tax issue: The filing may have been rejected, posted to another account or affected by a change in filing frequency.

Action: Review the state account history, submission confirmation, payment record and filing-frequency assignment before submitting another return.

Why this matters: A duplicate return can create a new reconciliation problem instead of solving the original one.

Common Mistakes When Responding to Sales Tax Notices

Mistake 1: Ignoring the notice because you believe it is wrong

A state error still needs to be resolved.

The correct approach is to document why the notice is wrong and respond through the applicable process.

Mistake 2: Calling the state before reviewing the facts

A phone call is not inherently harmful, but the person speaking for the company should understand the account history before making factual representations.

Review first.

Mistake 3: Paying an assessment without understanding it

Payment may be appropriate, but determine what created the liability first.

A notice can involve duplicated tax, estimated taxable sales, missing exemption documentation, misapplied payments or other issues that should be reconciled.

Mistake 4: Registering immediately after a nexus notice

Registration addresses prospective compliance. It does not by itself determine how historical exposure should be handled.

Analyze the historical period first.

Mistake 5: Assuming Amazon or another marketplace handled everything

Marketplace facilitator collection applies to facilitated transactions. It does not automatically resolve the seller’s direct sales, registration, return or historical obligations.

Mistake 6: Missing a formal protest deadline while corresponding informally

This can be particularly serious.

New York expressly warns that further correspondence or contact with the Department does not extend a statutory protest deadline.

Mistake 7: Sending unnecessary information

Respond to the issue raised and support the response with appropriate documentation.

More documents are not automatically better documents.

Actionable Sales Tax Notice Checklist

When a sales tax notice arrives:

Save the complete notice and envelope or portal record.
Record the notice date.
Identify the response or protest deadline.
Confirm the legal entity named.
Confirm the tax type.
Confirm the periods involved.
Verify the notice through the official state website or account.
Identify whether it is a request, audit notice, proposed assessment, bill or final determination.
Pull all relevant returns.
Pull payment confirmations.
Reconcile the state’s figures to your books.
Separate marketplace sales from direct sales.
Review exemption certificates where relevant.
Analyze economic and physical nexus if registration is questioned.
Determine when any obligation actually began.
Check whether other states may have similar exposure.
Evaluate whether VDA options remain available in states that have not contacted the business.
Determine whether the notice requires an informal response or formal protest.
Preserve appeal rights before the statutory deadline.
Keep copies of everything submitted and evidence of submission.

When Should You Get Professional Help?

Not every notice requires a major engagement.

A simple payment-posting error may be resolved with a payment confirmation and a short explanation.

Professional review becomes more important when the notice involves:

historical unregistered nexus,
multiple years,
multiple states,
substantial uncollected tax,
an audit,
estimated assessments,
large exempt-sale populations,
SaaS or digital-product taxability,
Amazon plus direct-channel activity,
responsible-person liability,
formal protest rights,
short appeal deadlines,
potential exposure in additional states.

State procedures can be unforgiving once an assessment becomes final.

California, for example, states that a Notice of Determination generally becomes final if a timely petition for redetermination is not filed.

Illinois likewise explains that a taxpayer must act within the specified protest period to use the listed administrative dispute procedures.

The time to evaluate a notice is therefore before a deadline removes options.

Conclusion

A sales tax notice should trigger analysis, not panic and not an automatic payment.

Start by identifying exactly what the state sent, verifying the notice, protecting the deadline and reconciling the state’s position against your own records. From there, determine whether the issue is administrative, related to filing, tied to nexus, part of an audit, or a formal assessment requiring protest.

For multistate businesses, the most important question may extend beyond the letter itself. A notice from one state can expose a wider compliance issue involving direct sales, marketplace activity, historical nexus or other jurisdictions.

Address the immediate notice, but also understand what caused it.

Need help making sense of your sales tax obligations? The experts at My Sales Tax Firm can help you navigate nexus studies, registrations, filings, audit defense, and ongoing compliance. Contact us today to learn more.

For MSTF’s broader sales tax support, visit the My Sales Tax Firm services page.

References:

Streamlined Sales Tax Governing Board, “Filing Sales and Use Tax Returns”
Official source
Supported guidance on filing obligations for registered sellers and the recommendation not to ignore state notices.
California Department of Tax and Fee Administration, Publication 17, “Appeals Procedures: Sales and Use Taxes and Special Taxes and Fees”
Official source
Supported California’s Notice of Determination petition procedures and 30-day filing period.
California Department of Tax and Fee Administration, Revenue and Taxation Code Section 6561 and Rule 35007
Section 6561
Supported the statutory finality and redetermination discussion.
Texas Comptroller of Public Accounts, “Auditing Fundamentals, Chapter 8”
Official source
Supported Texas audit redetermination timing and procedure.
Washington Department of Revenue, “How to File for an Excise Tax Review”
Official source
Supported Washington’s 30-day assessment review procedure and treatment of disputed amounts.
Illinois Department of Revenue, “Your Options to Dispute IDOR Deficiencies, Assessments, or Claim Denials”
Official source
Supported Illinois protest options and the generally applicable 60-day period for the specified notices.
New York State Department of Taxation and Finance, “Protest a Department Notice” and Publication 130-F
Protest guidance
Supported New York’s conciliation and Tax Appeals procedures and the warning that later correspondence does not extend applicable statutory deadlines.
Florida Department of Revenue, “Informal Dispute Resolution”
Official source
Supported the distinction between proposed assessments, return-related assessments, refund denials and notice-specific protest periods.
Multistate Tax Commission, “Multistate Voluntary Disclosure Program”
Official source
Supported the discussion of voluntary disclosure, prior state contact and multistate historical exposure.
Multistate Tax Commission, “Audit Program”
Official source
Supported the discussion of audit schedules, proposed adjustments, state assessments and taxpayer protest opportunities.
New York State Department of Taxation and Finance, “Report a Tax Scam”
Official source
Supported notice-verification and scam-prevention guidance.
Texas Comptroller of Public Accounts, Fraud and Consumer Alerts
Official source
Supported advice to verify suspicious state communications through independently obtained agency contact information.

FAQ

1. What should I do first if I receive a sales tax notice?

Identify the issuing agency, notice type, tax period, amount and response deadline. Then verify that the notice is genuine using the state's official website or taxpayer portal. Gather your relevant returns, payment records and transaction data before responding substantively. Do not assume the state's conclusion is correct, but do not ignore the notice simply because you disagree with it.

2. How long do I have to respond to a state sales tax notice?

There is no universal deadline. The period depends on the state and the type of notice. California generally provides 30 days for a petition involving a Notice of Determination, Washington generally uses a 30-day review period for an assessment, while Illinois generally provides 60 days for certain notices carrying protest rights. Always follow the deadline applicable to the actual notice you received.

3. What happens if I ignore a sales tax notice?

The consequence depends on the notice. A missing-return issue may progress to estimated billing or collection activity. An audit matter may advance without the documentation that could have supported your position. A formal assessment may become final if a required protest is not filed on time. Streamlined Sales Tax specifically advises businesses not to ignore state notices and to contact the relevant state when the reason for the notice is unclear.

4. Does receiving a sales tax notice mean I am being audited?

No. A notice may concern a missing return, registration, payment, nexus inquiry, account discrepancy, request for records, audit or assessment. Read the heading and instructions carefully. If the state has opened an audit, the notice normally identifies the audit period, tax type or examiner and explains the records or next steps required.

5. Can I dispute a sales tax assessment?

Often, yes, but procedures and deadlines vary. California uses petitions for redetermination for certain assessments. Texas provides redetermination procedures. Washington offers administrative review of assessments, and Illinois has administrative-hearing and Tax Tribunal routes for qualifying notices. New York allows qualifying notices to be challenged through a conciliation conference or Tax Appeals hearing.

6. What if the sales tax notice is from a state where I never registered?

Do not assume the notice is automatically wrong. Review whether your business had physical or economic nexus in the state during the periods involved. Analyze direct sales, marketplace activity, inventory, employees and other relevant facts. If historical exposure exists, determine its scope before completing registration or filing historical returns.

7. Can I still use a VDA after receiving a nexus notice?

Possibly not for the state that contacted you. Eligibility is state-specific. Under the Multistate Tax Commission's voluntary disclosure program, prior contact concerning the tax type, including receiving a state inquiry, can disqualify the taxpayer. A notice from one state does not automatically eliminate potential VDA options in other states that have not contacted the business.

8. Should I respond to a sales tax notice myself?

Simple administrative notices can sometimes be handled internally. Professional assistance becomes more valuable when the matter involves significant tax, historical nexus, audits, estimated assessments, multistate exposure, complex taxability questions or formal protest rights. The key is to have the facts and applicable state procedure reviewed before a response commits the business to an inaccurate position.

Sales Tax Notice From a State? What to Do Next