OBBBA international tax guidance is still in draft at filing time

What Treasury has actually issued, and what it has not

Miller & Chevalier's December 2025 review of the first OBBBA guidance wave set the shape of the problem: Treasury and the IRS moved on a narrow set of international provisions and left the rest for later. Proposed section 898 regulations are keyed to specified foreign corporation tax years beginning after 30 November 2025, which pulls controlled foreign corporation year-end alignment into this filing cycle rather than the next one. Proposed section 987 regulations reach further back, to tax years beginning after 31 December 2024, so branch functional currency mechanics are live for returns already being prepared.

The section 987 picture got no cleaner in the new year. The Internal Revenue Bulletin published in March 2026 showed Treasury still weighing three alternative approaches to basis on inbound transactions. That is not a drafting detail. It is a core mechanic for any group with qualified business units, and it was unresolved in the middle of filing season.

Layer on the corporate alternative minimum tax, where relief has continued to arrive by notice rather than regulation. Notice 2026-7 provided an adjusted financial statement income adjustment for eligible intangible amortization, per Holland & Knight's February 2026 analysis. Notices are useful and they are fast, but they are a thinner foundation than final regulations when an auditor asks how a position was supported.

Filing on proposed rules is an ASC 740 decision, not a tax decision

The practical consequence is that a filing choice becomes a reserve conversation. A position taken in reliance on a proposed regulation is rarely a clean more-likely-than-not conclusion, because the rule can change before it is finalized and the final version can pick a different one of the three approaches on the table. Under ASC 740, that pushes several cross-border items into the uncertain tax position column, with measurement judgments that the audit committee will see.

There are three realistic paths and each has a cost. File to the proposed regulations and accept that a final rule may force an amended return or an accounting method change. File to the statute and disclose the divergence, which invites examination attention but preserves flexibility. Or extend where the law allows and push the decision into a period with more information, accepting the close-calendar and interest consequences.

Whichever path a company picks, the budget line most often missed is remediation. Amended returns, method change filings and refreshed transfer pricing documentation are labor, not software. Wolters Kluwer's July 2026 work on tax research bottlenecks made the same point from the other direction: teams are spending more hours reaching less certain answers.

The close calendar changes before the numbers do

CFC year-end alignment under proposed section 898 and branch FX remeasurement under proposed section 987 do not just change the answer. They change who produces what, and when. Subsidiary controllers who used to deliver data on a familiar cadence may need to close earlier, and the FX remeasurement step that once sat late in the process may need to move ahead of the provision review.

That sequencing matters most in the run-up to the Q3 provision, where a late data pull turns into a late estimate and a late estimate turns into a disclosure conversation. Finance leaders who have not walked the revised close calendar with their controllers should do it before October, not after.

Pillar Two keeps moving on top of all of this

The global minimum tax overlay has not paused while OBBBA guidance catches up. Pillar Two still targets a 15% jurisdictional minimum rate for groups above 750 million euro in revenue, and BDO has noted that financial accounting effects persist until countries legislate new safe harbors. BDO Global and PwC both refreshed their implementation trackers within the past three weeks, which is itself the signal: the country-by-country position is still in motion.

For a multinational, that means two moving rule sets interacting. An OBBBA position that is uncertain domestically can change the jurisdictional effective tax rate that Pillar Two measures, and a safe harbor that lapses or is extended can change whether the interaction matters at all. Modelling one without the other produces a number that will not survive the next tracker update.

What to settle before mid-October

Three decisions should be documented now rather than argued later. First, a written position policy for each material OBBBA international item stating whether the company is following the proposed regulation or the statute, and why. Second, a reserve range agreed with the auditor, not presented to the auditor at the last review. Third, a remediation budget with named owners for amended returns and method changes if final rules diverge.

The operating environment will not help. Accounting Today's 2026 outlook found the share of practitioners expecting a worse filing season rose nine percentage points, attributed in part to OBBBA, and the Journal of Accountancy reported paper-return and refund delays tied to a smaller IRS workforce. Slower agency response is a planning assumption this year, not a complaint. Build it into the calendar.