What Is a 90-Day Deficiency Notice?

A 90-Day Letter is issued after the IRS completes an audit, examination, or review and determines additional tax is owed.

At this stage:

• The IRS has made its final determination

• The proposed tax is not yet assessed

• You have a strict statutory deadline to act

• You may file a petition in U.S. Tax Court

This is a legal dispute stage — not a collection notice.

Your Deadline Is Statutory

The 90-day deadline is fixed by law.

If you file a Tax Court petition within the deadline:

• The IRS cannot assess the tax while the case is pending

• You preserve your right to challenge the determination

• Settlement discussions may occur

If you miss the deadline:

• The tax is assessed

• Collection notices may follow

• Court rights are lost

What This Notice Is Not

A 90-Day Deficiency Notice is not:

• CP2000 (proposed income adjustment)

• CP504 (intent to levy)

• CP90 (final levy notice)

• A refund hold notice

This notice affects your right to challenge the IRS in court.

Common Mistakes

• Ignoring the statutory deadline

• Waiting until the last week to prepare documentation

• Failing to review every disputed issue

• Confusing this notice with collection notices

• Assuming you can extend the deadline

The deadline cannot be extended once expired.

What Happens If You Ignore It?

90-Day Deficiency Notice → Deadline Expires → Tax Assessed → Balance Due Notice (CP14) → Collection Escalation

This is your final opportunity to dispute before assessment.

Who This Documentation System Is For

✔ Taxpayers who disagree with the IRS determination

✔ Individuals considering filing a Tax Court petition

✔ Those organizing documentation before consulting an attorney or CPA

Not intended for:

✘ Active levy collection cases

✘ Refund verification matters

✘ Closed audit reconsideration requests

Frequently Asked Questions

What is a 90-Day Deficiency Notice?

A 90-Day Deficiency Notice (Statutory Notice of Deficiency) is the IRS’s formal determination that additional tax is owed after an audit or review. It gives you the legal right to petition the United States Tax Court before the IRS can assess the tax.

How long do I have to respond?

You have 90 days from the date printed on the notice (150 days if you are outside the United States) to file a petition with the U.S. Tax Court. The deadline is statutory and generally cannot be extended.

What happens if I miss the 90-day deadline?

If the deadline passes without a Tax Court petition being filed, the IRS may assess the tax and begin collection procedures. Once the deadline expires, your right to challenge the determination in Tax Court is permanently lost.

Is a 90-Day Letter the same as a levy notice?

No. A 90-Day Deficiency Notice is a legal dispute notice, not a collection notice. It affects your right to challenge the IRS determination before assessment. Levy notices (such as CP504 or CP90) occur during the collection phase.

Do I have to pay the tax before filing in Tax Court?

Generally, no. Filing a timely Tax Court petition allows you to dispute the proposed amount before it is assessed and before payment is required.

Can I still resolve the issue without going to court?

In some cases, settlement discussions may occur after a petition is filed. The 90-day window preserves your rights and creates leverage for procedural resolution.

What documents should I gather?

Typical documentation may include:

• Audit reports and examiner findings

• Supporting financial records

• Corrected calculations

• Legal or factual explanations for each disputed issue

• Prior correspondence with the IRS

Organized documentation is critical before the deadline.

Can the IRS extend the 90-day deadline?

No. The deadline is set by statute and generally cannot be extended, even for hardship or mailing delays.

What happens after I file a Tax Court petition?

Once a petition is properly filed within the deadline, the IRS is generally prevented from assessing the tax while the case is pending. The case may proceed through review, settlement discussions, or trial if unresolved.

90-Day Deficiency Documentation System

This structured system includes:

• Response Organization Framework

• Tax Court Petition Preparation Checklist

• Issue-by-Issue Dispute Worksheet

• Evidence Index Template

• Documentation Organization Guide

• Deadline Tracking Tool

• Escalation Planning Worksheet

Designed for organized, deadline-aware preparation.

Price: $399