Update: The National Taxpayer Advocate has published a blog post urging taxpayers to evaluate whether they have claims for refund based on the recent Abdo and Kwong decisions. Importantly, the Taxpayer Advocate suggests that the argument for penalty and interest relief based on the COVID pandemic disaster declarations is
When a Misdirected Partnership Notice isn’t Fatal under the BBA: Mammoth Cave Property
Although many of the procedural rules for auditing partnerships at the federal level have changed under the Bipartisan Budget Act of 2015 (the “BBA”), some principles—like the effect of actual notice—remain the same. Under the BBA, the IRS proposes partnership-level adjustments in a Notice of Proposed Partnership Adjustment (“NOPPA”) and later finalizes them in a Notice of Final Partnership Adjustment (“FPA”). If the IRS issues the FPA after the statute of limitations expires, the partnership can seek to invalidate it as untimely.
A reviewed Tax Court opinion filed March 9, 2026—Mammoth Cave Property, LLC v. Commissioner, No. 5401-24, 166 T.C. No. 4—shows the limits of “defective notice” arguments when the partnership actually received the NOPPA and participated in the process.
Fifth Circuit in Sirius Solutions Reverses Tax Court and Exempts Limited Partners from Self-Employment Tax
On January 16, 2026, in Sirius Solutions, L.L.L.P. v. Commissioner,[1] No. 24-60240 (5th Cir. Jan. 16, 2026), the U.S. Court of Appeals for the Fifth Circuit reversed the Tax Court and held that, for self-employment tax purposes, a “limited partner” means “a partner in a limited partnership that…
Treasury and the IRS Release Final and Proposed Regulations on Section 892
I. Introduction
On December 15, 2025, the U.S. Department of the Treasury (“Treasury”) and the Internal Revenue Service (the “IRS”) published final regulations (the “Final Regulations”) and proposed regulations (the “Proposed Regulations”) under section 892.[1] The Final Regulations finalize, with modifications…
How Relevant Is It? The Economic Substance Doctrine According to Liberty Global and Patel
I. Introduction
Should courts respect a transaction for tax purposes, when it otherwise complies with the technical requirements of the Internal Revenue Code and regulations? When should a court take the next step and consider the economic substance of a transaction and its motivations?
In two highly-awaited court decisions…
Proposed Regulations Remove Look-Through Rule for Domestically Controlled REITs
I. Introduction
On October 20, 2025, the U.S. Department of the Treasury (“Treasury”) and the Internal Revenue Service (the “IRS”) issued proposed regulations (the “Proposed Regulations”) that would helpfully revoke the current “look-through rule” for domestic C corporation shareholders to determine whether a “real…
Eighth Circuit Affirms Mayo Clinic’s “Educational Organization” Status and UBTI Refund
On July 25, 2025, the U.S. Court of Appeals for the Eighth Circuit affirmed the District Court decision holding that the Mayo Clinic is entitled to an $11.5 million refund of certain unrelated business income taxes imposed on it due to it being an “educational organization” under section 170(b)(1)(A)(ii).[1]…
Tax Court Breaks New Ground on the Deductibility of Termination Fees with AbbVie Ruling
On June 17, 2025, the Tax Court opinion in AbbVie Inc. and Subsidiaries v. Commissioner of Internal Revenue was issued,[1] holding that the approximately $1.6 billion termination fee AbbVie (a Delaware corporation) paid to its abandoned merger partner Shire plc (an Irish company) was properly an ordinary deductible business…
The Tax Court in Soroban Holds that Limited Partners Were Too Active To Be Treated As “Limited Partners” and are Subject to Self-Employment Tax
On May 28, 2025, in Soroban Capital Partners LP v. Commissioner (T.C. Memo 2025-52) (“Soroban II”), the Tax Court held the active role of limited partners in a fund manager caused them to fail to qualify as “limited partners” for purposes of section 1402(a)(13) and, therefore, the limited…
IRS and Treasury Announce Withdrawal of Related Party Basis Shifting Regulations
On April 17, 2025, the U.S. Internal Revenue Service (the “IRS”) issued Notice 2025-23 (the “Notice”), announcing its intention to withdraw the recently released final regulations final regulationsthat classify certain partnership related party basis shifting transactions and substantially similar transactions as “transactions of interest”. The Notice provides taxpayers and their…