Tax Bytes: Week of January 12, 2026

Tax developments

IRS provides new option for navigating differences between customs and transfer pricing values

As tariffs on goods imported into the United States keep changing, the interplay between customs values and transfer pricing has become more significant. Until recently, the IRS generally would not rule on whether a taxpayer's cost or inventory basis in property imported from a foreign affiliate would be limited by section 1059A due to differences between customs valuation and income tax valuation. However, on January 5, 2026, the IRS removed section 1059A from its no-rule list and has already begun issuing rulings. By making the letter ruling process available to taxpayers, the IRS may help taxpayers gain certainty on how section 1059A applies in the context of their controlled transactions.

Read our full alert here.

What a relief: OECD releases Pillar Two Side-by-Side Package

On January 5, 2026, the OECD published the Global Anti-Base Erosion Model Rules (Pillar Two), Side-by-Side Package (side-by-side package), following months of negotiations. The side-by-side package extends and introduces new safe harbors from application of Pillar Two Income Inclusion Rules (IIR) and Under Taxed Profits Rules (UTPR). These significant changes should provide immediate relief to US and non-US headquartered companies in 2026, and are designed to allow for an orderly transition to a simplified application of Pillar Two Rules in future years.

Read our full alert here.

Stamp to confirm your filing date: New postal regulation reinforces best practices in tax controversies

Effective December 24, 2025, the US Postal Service (USPS) implemented a new rule that fundamentally changes how postmarks are defined under the Internal Revenue Code’s so-called “mailbox rule.”

Read our full alert here.

Recent Eversheds Sutherland Tax insights

Swiss Tax – The One Pager

Irish Department of Finance publishes Feedback Statement for phase one of reform of Ireland’s taxation regime for interest

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