Letter 531

A Letter 531 is a statutory notice of deficiency, issued after an in-person audit (its mail-audit twin is Letter 3219). It is often called 'your ticket to the Tax Court': it is the legal notice that gives the right to challenge the proposed tax in court before paying a dollar of it. The IRS cannot assess the deficiency without first giving you this chance.

“We propose this deficiency, detailed in the enclosed audit report. Sign Form 5564 if you agree. If you don't, you have 90 days from the date on this notice to petition the United States Tax Court — 150 if you're outside the country. We'll still work with you during those 90 days, but nothing extends the court deadline.”

This deadline is prescribed by law: the IRS cannot extend it and a late petition is dismissed. The petition goes to the Tax Court, not the IRS, and can be filed electronically until 11:59 p.m. Eastern on the last day. Even people who hope to settle with the IRS often file the petition anyway — it preserves the forum while talks continue. Missing it isn't quite the end (audit reconsideration exists) but it surrenders the strongest position.

• The complete notice with the printed petition date, plus the enclosed audit report and Form 5564
• The full audit file and correspondence history
• Documentation for every item you'd still contest
• A calendar with the 90th day marked, immediately

• The strategic call: petition, negotiate, or both in parallel — and making it early, not on day 85
• Preparing and filing the Tax Court petition (fee waivers exist for those who need them)
• Continuing settlement talks with the IRS or Appeals while the petition protects the deadline
• Audit reconsideration if the deadline has already passed