Two Different Questions Wearing Similar Clothes
Domestic content asks a simple question: how much of this project's steel, iron, and manufactured products came from the United States? It's been around since the IRA, the categories are familiar, and Treasury's existing safe harbor tables give developers a known path to the bonus percentage.
FEOC material assistance asks a different question: how much of this project's cost came from a prohibited foreign entity, regardless of whether that entity is foreign at all. A component manufactured entirely in the United States can still fail the material assistance test if the company making it is majority-owned or effectively controlled by a specified foreign entity. Domestic content cares about geography. FEOC cares about ownership and control. Those are not interchangeable filters, even though both produce a percentage at the end.
Where the Overlap Creates False Confidence
The confusion isn't accidental. Notice 2026-15 allows taxpayers to lean on the existing domestic content safe harbor tables as an interim method for calculating the material assistance cost ratio. That's a practical bridge while permanent MACR tables are being built, but it's also created a habit of treating the two calculations as one exercise with two names.
They diverge in ways that matter. The facility-level MACR calculation for 45Y and 48E includes direct labor costs in its denominator. The Section 45X version for eligible components does not. Domestic content safe harbor percentages and FEOC threshold percentages are set on entirely different schedules and increase at different rates over time. A project can clear its domestic content bonus threshold comfortably while sitting well below its required MACR, or the reverse, depending on where its foreign-sourced content actually comes from and who owns the entity supplying it. The year-over-year escalation on both schedules, and what it means for projects that slip past a construction-start deadline, is laid out in the 2026 supply chain trap breakdown on surviving FEOC limits and the Direct Pay haircut under Section 48E.
Why This Matters Beyond Clean Energy
This distinction is worth understanding even outside the tax credit world, because it reflects a pattern showing up across trade and industrial policy more broadly. Country-of-origin compliance and ownership-based compliance are being layered on top of each other, and they don't move in sync. A supplier can be geographically domestic and still carry ownership risk. A component can be foreign-made and still clear a control test if the ownership structure is clean. Any industrial buyer running procurement decisions off a single sourcing checklist is going to miss half the picture.
Building the Right Model
The practical fix is separating the two calculations at the outset rather than trying to retrofit one into the other. That means tracking sourcing geography and ownership structure as two distinct data points for every supplier and component, not one combined score. It also means revisiting supplier certifications to confirm they answer both questions, since a certification built for domestic content purposes often says nothing about who actually controls the entity issuing it.
Until Treasury finalizes the safe harbor tables required under Section 7701(a)(52), developers are working with two moving targets instead of one. Treating them as a single compliance exercise might save time in the short term, but it's the kind of shortcut that shows up later as a recapture problem nobody saw coming.
This same gap in verified guidance is why insurers are struggling to price FEOC risk cleanly, and why public companies face a related but distinct challenge in certifying their own ownership status.