Letter 4389, Notice of Determination - Abatement of Interest, is issued at the end of a timely Collection Due Process hearing in which you also asked the IRS to abate interest under IRC Section 6404. It is a Notice of Determination, which means it carries the right to petition the United States Tax Court.
Two Issues, Two Deadlines
The collection part of a CDP determination carries a 30-day petition deadline under IRC Section 6330(d). A petition challenging a final determination not to abate interest is governed by IRC Section 6404(h), which allows 180 days. The letter states the timeframe that applies. If you intend to challenge both the collection decision and the interest decision, file within 30 days and protect everything at once.
When Interest Abatement Is Available
Interest abatement is narrower than most people expect. IRC Section 6404(e) allows abatement of interest attributable to an unreasonable error or delay by an IRS employee in performing a ministerial or managerial act, after the IRS contacted you in writing about the deficiency or payment. It does not cover delay caused by the taxpayer, and it does not cover the IRS simply taking a long time to make a judgment call. The Tax Court reviews these decisions for abuse of discretion.
Read the determination closely. If Appeals denied interest abatement, the explanation will tell you whether it rejected the facts you alleged or the legal theory.
If you received Letter 4389, call us at (813) 229-7100. The petition clock starts on the date of the letter.