Tax Coda Weekly Digest — January 25, 2026

Most tax cases do not move doctrine. This week suggested why the old ones are being tested anyway.

Courts revisited foundational standards. Congress pulled back resources. Whistleblower incentives narrowed. And the IRS continued publishing mechanical guidance amid shrinking capacity.

1. Why Foundational Tax Doctrines Are Back on the Table

We examined why doctrines like economic substance, substance over form, and business purpose are resurfacing in modern cases. Most disputes still resolve on facts, not theory. But as transactions grow more engineered, courts lean on doctrine to resolve gaps the Code cannot anticipate.

Why It Matters:

• Doctrines fill statutory blind spots.

• Litigation risk increases when transactions push technical limits.

• Courts rely on doctrine when facts strain credibility.

Takeaway:
Doctrines return when statutes stop explaining outcomes.

2. IRS Funding Clawback Tightens Agency Operating Cushion

Congress moved to rescind another $11.66 billion from the IRS’s supplemental fundi…