Domestic Content Compliance Playbook for Mid-Market Procurement

Current as of 14 October 2026. Statutory and IRS guidance were read in primary form; court, trade and market items rely on named secondary sources. Nothing in this guide is legal, tax or accounting advice.

Part IExecutive Summary

For a mid-market solar buyer in late 2026, Domestic Content is no longer a stand-alone bonus calculation. Every project that begins construction in 2026 or later must also pass the Material Assistance Cost Ratio (MACR) test, which runs on the same IRS cost tables but asks a different question. The procurement file that proves one test should be built to prove the other.

This playbook is written for the 1–20 MW segment: commercial, industrial, community, municipal and small utility projects, where a single procurement officer or EPC often carries the whole documentation burden without a tax-equity investor's diligence team behind it. It sets out the rules as they stand on 14 October 2026, shows the arithmetic behind the IRS safe-harbor tables, and provides three working templates — a supplier vetting questionnaire, an audit-file checklist and an RFQ-to-return timeline — that counsel can adapt.

Conclusions

1. The Domestic Content rules did not change in 2026; the threshold did. Notice 2023-38, as modified by Notices 2024-41 and 2025-08, still governs, and no proposed regulations have been published. Under §48E, the adjusted percentage is 50% for projects that begin construction during 2026 and 55% for starts after 31 December 2026. Material written in 2023–2025 that cites a 40% threshold should not be reused for current projects.
2. Every 2026-start project now faces two cost-ratio tests built on one set of tables. Domestic Content is an optional bonus; the MACR test is a condition of claiming the credit at all, with a 40% facility threshold for 2026 starts and 45% for 2027 starts. Both run on the Notice 2025-08 tables, so a single bill-of-materials (BOM) file, tracking origin and producer for each listed component, should serve both.
3. The 1 MWac line is the most important number for mid-market buyers. Below it, the full 10-point Domestic Content ITC bonus is available without meeting prevailing wage and apprenticeship (PWA) requirements, and the direct-pay haircut does not apply. Above it, a project that does not meet PWA earns only a 2-point bonus, and a direct-pay project that does not meet Domestic Content faces the haircut.
4. For direct-pay buyers, Domestic Content is effectively mandatory at 1 MWac and above. For facilities that begin construction after 31 December 2025, the elective-payment applicable percentage for a non-compliant project of 1 MWac or more is 0%. The only alternative is the increased-cost or non-availability exception, attested under Notice 2024-84 for construction starts before the later of 1 January 2027 or further guidance.
5. The Five Percent Safe Harbor is back, but the calendar has moved on. The vacatur restored the 5% method for establishing beginning of construction. Wind and solar facilities that begin construction after 4 July 2026 must be placed in service by 31 December 2027 to claim §48E, so for most new mid-market projects the operative constraint is now the placed-in-service deadline.
6. A U.S.-assembled module with imported cells reaches at most about 23% of the ground-mount tracker table. That ceiling assumes every non-cell module component on the table is U.S.-made; the module's "Production" share is lost because a listed component (the cells) is foreign. Clearing 50% without U.S. cells requires U.S. trackers or racking as well, which lifts the computed maximum to 51.8%.
7. A fully U.S. module with U.S. cells is worth 65.8% of the ground-mount tracker table on its own. Using the domestic-cell-and-wafer column, it is worth 73.4%. On fixed-tilt ground mounts the module carries 92.5% of the table. In these cases the module alone can clear 50% — but only if every listed module component is U.S.-made.
8. Supplier paper is now regulated, and many letters in circulation do not meet the standard. MACR supplier certifications must carry the supplier's EIN, be signed under penalties of perjury and be retained for at least six years; suppliers face a §6695B penalty for inaccurate certifications provided after 31 December 2025. Manufacturer letters that disclaim tax reliance and omit the EIN and perjury statement do not satisfy that standard.
9. Audit exposure has grown materially. For credits disallowed because the MACR was overstated, the substantial-understatement threshold falls from 10% to 1%; the IRS has six years to assess MACR errors; excessive direct payments and excessive credit transfers carry a 20% addition; and a 10-year, 100% recapture applies to certain effective-control payments on §48E property.
10. Three dates belong on every mid-market procurement calendar. The §232 tariff and minimum import prices take effect on 4 December 2026; Treasury's statutory deadline for MACR safe-harbor tables is 31 December 2026, with interim reliance on the current tables ending 60 days after publication; and the Notice 2024-84 exception-attestation route runs to the later of 1 January 2027 or further guidance.

At a glance: thresholds and dates

P.L. 119-21 §§70512–70513; 26 U.S.C. §§45Y(g)(11)–(12), 48E(a)(3)(B), 48E(e)(4); new §7701(a)(52); Notice 2024-84; Hunton (11 Aug 2026); Wiley (7 Aug 2026). Solar facilities that begin construction after 4 Jul 2026 must be in service by end-2027, so 2028+ MACR facility thresholds matter mainly for storage and non-solar technologies.

Section 1The rulebook in October 2026

Mid-market buyers are working under a guidance stack that is three years deep in places and nine months old in others. Knowing which document governs which question is the first compliance control.

1.1 The statutory map

The One Big Beautiful Bill Act (P.L. 119-21), enacted on 4 July 2025, rewrote the technology-neutral credits rather than repealing them. Section 70512 amended the §45Y production credit, §70513 amended the §48E investment credit and §70514 amended the §45X manufacturing credit. Three of those amendments matter most for procurement.

First, the Domestic Content bonus thresholds were re-stepped. Under §48E(a)(3)(B), the adjusted percentage that applies to manufactured products is 40% for projects that began construction before 16 June 2025, 45% from 16 June through 31 December 2025, 50% during 2026 and 55% thereafter. The §45Y schedule reaches the same 50% and 55% figures, but its break point between 40% and 45% is 1 January 2025 rather than 16 June 2025 — a detail worth noting for anyone reconciling legacy PTC files.

Second, a "prohibited foreign entity" (PFE) regime was added. New §7701(a)(51) defines specified foreign entities and foreign-influenced entities; new §7701(a)(52) defines the Material Assistance Cost Ratio and its thresholds. Under §48E(b), the material-assistance disallowance applies to facilities whose construction begins after 31 December 2025.

Third, wind and solar received a terminal date. Under §48E(e)(4), the credit does not apply to wind or solar facilities placed in service after 31 December 2027 if construction began more than twelve months after enactment — that is, after 4 July 2026. Energy storage placed in service at such a facility is excepted from this termination.

The underlying Domestic Content mechanics remain in §45(b)(9), incorporated by reference: the taxpayer certifies that steel, iron and manufactured products that are components of the facility at completion were produced in the United States, applying the Buy America rules of 49 CFR Part 661. Steel and iron follow the 100% standard of 49 CFR 661.5; manufactured products are deemed domestic if at least the adjusted percentage of their total cost is attributable to U.S.-mined, produced or manufactured components.

1.2 The guidance stack

IRS Notices 2023-38, 2024-41, 2024-84, 2025-08, 2025-42, 2026-15; Internal Revenue Bulletins 2026-02 to 2026-42; Instructions for Form 3468 (2025); draft Form 3468 (2026) and draft instructions (15 Sep 2026); Federal Register API (to 14 Oct 2026); Clifford Chance (4 Sep 2026).

1.3 What did not happen in 2026

The absence of guidance is itself a planning fact. Our full-text scan of Internal Revenue Bulletins 2026-02 through 2026-42, and a Federal Register query of IRS documents published since 1 January 2026, found:

• No new Domestic Content notice, proposed regulation or updated table. The only 2026 IRS references to domestic content are cross-references in Notice 2026-37 (§45 inflation factors) and Notice 2026-39 (energy communities).
• No MACR-specific safe-harbor tables. The statute requires Treasury to publish them by 31 December 2026.
• No proposed PFE regulations for §§45Y, 48E or 45X. The only 2026 PFE proposed rule in the Federal Register relates to the §45Z clean fuel credit (4 February 2026).

The practical consequence is stability for the remainder of 2026: a project file built today on Notice 2023-38 and the Notice 2025-08 tables rests on guidance that has been in place since January 2025. The risk sits in 2027, when MACR tables and PFE regulations are expected and may diverge from the Domestic Content tables.

1.4 What did happen

The vacatur of Notice 2025-42. Notice 2025-42, issued on 15 August 2025 following Executive Order 14315, had removed the Five Percent Safe Harbor for wind and solar facilities except "low output" solar facilities of 1.5 MWac or less, for projects that had not begun construction before 2 September 2025. On 6 June 2026 the District Court for the District of Columbia vacated the notice nationwide. Practitioner summaries report that the court found the change in policy inadequately explained, reliance interests unconsidered and the different treatment of wind and solar unjustified. After vacatur, the prior framework — Notices 2013-29 and 2018-59, and Notice 2022-61 for §§45Y/48E — again offers either the Physical Work Test or the 5% safe harbor, plus the continuity requirement. The statutory 4 July 2026 cliff was unaffected. According to Clifford Chance (4 September 2026), no notice of appeal was filed within the 60-day window that closed on 5 August 2026, and any motion to extend the appeal deadline was due by 4 September 2026. As of 14 October 2026, we had identified no appeal, stay or extension in published reports. Treasury has not issued replacement guidance: none appears in Internal Revenue Bulletins through IRB 2026-42 or in the Federal Register through 14 October 2026, and the IRS's draft 2026 Form 3468 instructions (15 September 2026) describe the physical work test and the 5% safe harbor as available methods without a wind/solar limitation.

For projects that began construction between 2 September 2025 and 6 June 2026, many developers relied on physical work alone. Practitioners recommend documenting both tests where the facts allow.

Notice 2026-15. Released on 12 February 2026 (IR-2026-23) and published at 2026-11 I.R.B. 658, the notice supplies the working rules for MACR. It is discussed in Section 3.

Trade measures. The §232 proclamation on polysilicon and its derivatives and the FCC's inverter action are not tax rules, but both push sourcing decisions toward U.S.-made cells and inverters — the same components that carry the most weight in Domestic Content arithmetic.

Chart 01 · Timeline

The regulatory calendar a 1–20 MW buyer is working against

Guidance, court and trade events, January 2025 to December 2027

Chart 02 · Market context

The segments this playbook serves

U.S. solar installations by segment, Q2 2026 (GWdc)

Section 2Thresholds, timing and what the bonus is worth

Three dates fix a project's compliance targets: the beginning-of-construction date sets the thresholds, the placed-in-service date fixes when compliance is measured, and the filing date starts the assessment clock.

2.1 The adjusted-percentage schedule

The Domestic Content test has two limbs. The steel or iron requirement is binary: every structural steel or iron construction material must be produced entirely in the United States. The manufactured products requirement is a ratio: the Domestic Cost Percentage of all manufactured products must meet the adjusted percentage for the project's construction-start year — 50% for 2026 starts under §48E, and 55% for starts after 31 December 2026.

The MACR schedule rises more steeply but starts lower. For qualified facilities, the threshold is 40% for 2026 construction starts, rising by five points each year to 60% for starts after 2029. Energy storage starts at 55% and reaches 75%. For §45X component manufacturers, the thresholds for solar components run from 50% for 2026 sales to 85% after 2029, and for inverters from 50% to 70%.

Chart 03 · Thresholds

Two thresholds, one bill of materials

§48E Domestic Content adjusted percentage versus MACR thresholds, by beginning-of-construction period

2.2 The steel and iron rule: narrower than it looks

The 100% steel/iron standard applies only to applicable project components that are construction materials made primarily of steel or iron and structural in function. Under Notice 2023-38, for a ground-mount PV system that means steel module racking (fixed tilt), piles or ground screws and reinforcing steel in foundations. It does not reach steel incorporated inside a manufactured product — the steel in a tracker's torque tube, for example, is tested as part of the tracker under the manufactured-products ratio — and non-structural items such as nuts, bolts, clamps and covers are excluded.

The steel/iron test is satisfied only if all manufacturing processes, from initial melting through coating, take place in the United States, with an exception for metallurgical processes that refine steel additives. Mill certificates and fabricator attestations are the usual evidence.

2.3 Beginning of construction after the vacatur

Beginning of construction (BOC) can be established by either method under the pre-2025 framework:

• Physical Work Test: physical work of a significant nature, on-site or off-site under a binding written contract.
• Five Percent Safe Harbor: paying or incurring at least 5% of the total cost of the facility.

Either way, the taxpayer must then show continuous progress. The continuity safe harbor is met if the facility is placed in service by the end of the fourth calendar year after the year construction began; a 2026 start therefore runs to 31 December 2030 — but for wind and solar, the statutory 31 December 2027 placed-in-service deadline overrides that for any start after 4 July 2026.

BOC for PFE purposes follows rules similar to Notices 2013-29 and 2018-59 as in effect on 1 January 2025, by statute. Notice 2026-15 confirms that Notice 2025-42 never applied to PFE beginning of construction.

2.4 What the bonus is worth

For the §48E investment credit, the Domestic Content bonus adds 10 percentage points if the project meets the PWA requirements of §48(a)(9)(B), and 2 points otherwise. The IRS explains that the 10-point increase applies where the project is under 1 MW, began construction before 29 January 2023, or meets PWA. For the §45Y production credit, the bonus is 10% of the credit amount.

A simple way to frame the procurement decision is to translate the bonus into dollars against the credit-eligible basis, and compare that against the price premium for compliant equipment and the cost of documentation.

Chart 04 · Illustrative

The value of the Domestic Content bonus scales with basis — and depends on PWA

Illustrative: ITC bonus value at 10 points versus 2 points, by credit-eligible basis

On a hypothetical $5 million eligible basis, the 10-point bonus is worth $500,000 and the 2-point bonus $100,000. On a $20 million basis, the figures are $2.0 million and $0.4 million. For a project of 1 MWac or more that does not meet PWA, the 2-point bonus rarely justifies the documentation effort on its own; the decision then turns on whether the buyer needs Domestic Content to avoid the direct-pay haircut (Section 5).

Section 3Domestic Content and MACR: same tables, different question

Domestic Content asks whether a component was made in the United States. MACR asks whether it was made by a prohibited foreign entity. A component can pass one test and fail the other — and a project must pass MACR before the Domestic Content bonus means anything.

3.1 How the Domestic Cost Percentage is calculated

Under Notice 2023-38, a manufactured product is a U.S. Manufactured Product if all of its manufacturing processes take place in the United States and all of its manufactured product components (MPCs) are of U.S. origin. An MPC is of U.S. origin if it is manufactured in the United States, regardless of where its own subcomponents came from. This is the "one level down" rule: a U.S.-made junction box counts as domestic even if its diodes are imported.

The Domestic Cost Percentage is the ratio of domestic manufactured products and components cost to total manufactured products cost. Under the actual-cost method, costs are the manufacturer's direct materials and direct labour, not the price the buyer paid, and installation labour is excluded. Notice 2023-38's own example arrives at 60% ($180 of $300). Because few module manufacturers will release direct-cost data, most mid-market buyers rely instead on the elective safe-harbor tables discussed in Section 4.

"United States" for this purpose includes the 50 states, the District of Columbia, Puerto Rico, Guam, American Samoa, the U.S. Virgin Islands and the Northern Mariana Islands.

3.2 Who is a prohibited foreign entity

A PFE is either a specified foreign entity (SFE) or a foreign-influenced entity (FIE). Notice 2026-15 summarizes the SFE categories as:

• foreign entities of concern under NDAA §9901(8);
• Chinese military companies on the DoD 1260H list;
• entities on the UFLPA Entity List;
• entities designated under FY2024 NDAA §154(b);
• foreign-controlled entities, including agencies or instrumentalities of covered-nation governments.

An entity is foreign-influenced during a taxable year if any of the following holds:

• an SFE has direct authority to appoint a covered officer;
• a single SFE owns at least 25% of it;
• SFEs in aggregate own at least 40%;
• at least 15% of its debt is issued to SFEs;
• in the previous taxable year, it made payments to an SFE under an arrangement giving the SFE effective control.

Modified rules apply to publicly traded entities.

The interim effective-control definition in Notice 2026-15 covers unrestricted contractual rights to set production, dispatch or offtake, to restrict data or site access, or to perform operations and maintenance exclusively. It also lists IP licensing indicators, including any licence entered into or modified on or after 4 July 2025. The notice illustrates that royalty payments to an SFE under such a licence for the facility can make the taxpayer itself a foreign-influenced entity.

3.3 The Clean Electricity MACR in five steps

Notice 2026-15 defines the Clean Electricity MACR as total direct costs minus PFE total direct costs, divided by total direct costs. It covers manufactured products and MPCs incorporated into the facility on completion; steel and iron items are disregarded unless they are themselves manufactured products or components. In practice:

1. Identify the manufactured products and MPCs incorporated at completion.
2. Assign costs, either actual direct costs or table percentages under the safe harbors.
3. Determine the producer of each item — the entity that mined, produced or manufactured it, not a reseller.
4. Test PFE status of each producer for its taxable year that includes the date the taxpayer paid or incurred the cost (for accrual taxpayers, when the item is provided). An item paid for in 2026 and placed in service in 2027 is tested on the producer's 2026 status.
5. Compute and compare the ratio to the threshold for the facility's BOC year.

Two simplifications help mid-market buyers. A 10% de minimis rule removes the need to track individual items of the same type whose total direct costs are below 10% of the facility's total direct costs. And the safe harbors allow the Notice 2025-08 tables to stand in for actual costs.

Notice 2026-15 also notes that qualified interconnection property needs its own MACR. Failing that test removes only the interconnection costs from the credit base; a facility that fails its MACR loses the whole credit.

3.4 The three MACR safe harbors

Notice 2026-15 §§4.01–4.03, 8.02.

A taxpayer using any of these safe harbors must attach a statement to the return for the first credit year that names the safe harbor, identifies the table used and explains how it was applied.

Chart 05 · MACR examples

Notice 2026-15's own examples clear the 2026 threshold comfortably

MACR results in two worked examples from the notice, versus the 2026 and 2027 facility thresholds

Notice 2026-15's Example 1 is instructive for buyers of imported modules. Where the only PFE-produced item is the cells (38.0% of the ground-mount tracking table) and bypass diodes are unused (0.4%, removed from the denominator), the MACR is (99.6 − 38.0) ÷ 99.6 = 61.8%. In other words, a facility can comfortably pass MACR while scoring zero on Domestic Content — the two tests are genuinely independent.

3.5 Side by side

Notice 2023-38; Notice 2025-08; Notice 2026-15; P.L. 119-21 §70512.

Section 4The safe-harbor tables, explained with arithmetic

For most 1–20 MW buyers, the Notice 2025-08 tables are the Domestic Content calculation. They replace manufacturer cost data with fixed percentages, so the buyer's task becomes proving origin, row by row. The arithmetic below shows where the weight sits — and how quickly a compliant-looking BOM can fall short.

4.1 How the elective safe harbor works

Notice 2025-08 (released 16 January 2025) created the First Updated Elective Safe Harbor. It provides cost-percentage tables for ground-mount PV (tracking and fixed) and rooftop PV (module-level power electronics, "MLPE", and string inverter). Each table has a standard column and a "domestic c-Si cells and domestic wafers" column. The rules that govern their use are strict:

• Exclusive and exhaustive. Only the listed applicable project components (APCs) and MPCs count. Unlisted items are disregarded and cannot add to the percentage.
• Unused rows score zero. A listed item the project does not use is valued at zero for Domestic Content.
• No partial reliance. The whole table section for the project type must be used. A taxpayer must use either the Notice 2024-41 or the Notice 2025-08 safe harbor, not a mix.
• "Production" is conditional. Each manufactured product has a "Production" row. It is not an MPC, and its percentage counts only if all listed MPCs of that product are U.S.-produced. Unlisted MPCs do not block it.
• Mixed sources are weighted by nameplate. Where an item comes partly from U.S. and partly from foreign sources, a capacity-weighted formula applies; items without nameplate (such as trackers) use the capacity of the modules directly integrated with them. If a single component has both foreign and domestic units integrated with it, all are treated as foreign.
• Election on the certification statement. The Domestic Content Certification Statement must state reliance on the safe harbor.

The safe harbor applies to construction starts from 16 January 2025 until 90 days after any modification or withdrawal; none had occurred as of 14 October 2026. Note that the notice's own examples use 100 MWdc projects tested at a 40% threshold, which predates the OBBBA schedule — the 2026 threshold is 50%.

4.2 The ground-mount table

IRS Notice 2025-08 §5.05 (extracted from the notice PDF; footnote markers removed). DCW = domestic c-Si cells and domestic wafers column. Each column sums to 100.0. Subtotals computed by SolarStock USA Research and cross-checked against Notice 2026-15 Example 1, which states 65.8% / 5.5% / 28.7% for the tracking column.

4.3 The rooftop table

IRS Notice 2025-08 §5.06. Small rows combined for space (each listed separately in the notice; the MLPE column has no thermal-management row). Subtotals computed by SolarStock USA Research.

Chart 06 · Table structure

Where the cost weight sits in each table column

Share of each Notice 2025-08 table column by applicable project component (%)

Three structural features stand out. On fixed-tilt ground mounts, the module is effectively the whole calculation (92.5%), because steel racking sits outside the ratio. On tracker projects, the tracker carries nearly 29% — more than any single module component other than cells. And on MLPE rooftops, the inverters and optimizers carry 24.8%, which makes U.S.-made MLPE a meaningful lever for commercial rooftop buyers.

Chart 07 · Component detail

Cells dominate; the domestic-wafer column makes them dominate more

Ground-mount tracking table: largest listed rows, standard column versus domestic-cell-and-wafer column (%)

4.4 Worked arithmetic: how far a module gets you

The scenarios below apply the ground-mount tracking column. Each assumes every named item is U.S.-made and every other item is foreign. They are maximums under each scenario, not typical outcomes.

COMPUTED by SolarStock USA Research from IRS Notice 2025-08 §5.05 tracking column. Illustrative; assumes full documentation of U.S. origin for every counted row.

Chart 08 · Ground-mount tracking

How far a module gets you

Maximum Domestic Cost Percentage by BOM scenario, ground-mount tracking column, stacked by contribution (%)

4.5 The same scenarios across project types

COMPUTED by SolarStock USA Research from Notice 2025-08 standard columns. Fixed-tilt projects must separately meet the 100% steel/iron test for racking, piles and foundation steel.

Chart 09 · Scenario grid

Without U.S. cells, only tracker and MLPE configurations get close

Maximum Domestic Cost Percentage, scenarios S1–S5 by project type (%)

Read across, the grid gives a clear procurement rule. Without U.S. cells, a fixed-tilt ground mount cannot reach 50% under the safe harbor at all — the ceiling is 40.1% even with a U.S. inverter. A string rooftop reaches 54.3% only if module materials, racking and inverter are all U.S.-made. A tracker project can clear 50% without U.S. cells only by combining U.S. module materials with a U.S. tracker, with less than two points to spare. With U.S. cells, the module carries ground-mount projects across the line on its own.

4.6 How a compliant-looking BOM erodes

The commonest gap in real BOMs is not the cell but the commodity materials — glass, encapsulant and backsheet are often imported even for U.S.-assembled modules. Each foreign MPC subtracts its own row and removes the module's Production share.

Chart 10 · Illustrative

Three imported commodity materials can take a U.S.-cell module below 50%

Illustrative erosion of the ground-mount tracking module subtotal (%), starting from scenario S4

In this illustration, a module with U.S. cells but imported glass, encapsulant and backsheet scores 47.5% — below the 2026 threshold — and the project would need a U.S. tracker to recover. The lesson for the RFQ is that "U.S. cells" is a necessary question but not a sufficient one: every listed MPC needs an origin answer.

4.7 The domestic cell-and-wafer columns

The DCW columns are available only if all or part of the modules use U.S. c-Si cells made exclusively from U.S. wafers. If a project elects them, it must use them for every item, and any U.S. cells made on foreign wafers must be treated as foreign — which also strips those modules of the Production share. The DCW columns reward a fully domestic cell chain (cells rise from 38.0% to 51.6% in the tracking column). No guidance specifies the evidence standard for tracing U.S. wafers to cell lots; this is an open question (Section 13).

4.8 A note on the MACR reading of the same tables

When the same tables are used for MACR under Notice 2026-15, two conventions differ from Domestic Content. Listed-but-unused items are disregarded — removed from the denominator — rather than valued at zero, which is why Example 1 divides by 99.6 rather than 100. And steel/iron rows are disregarded entirely. A single workbook can serve both tests, but it needs two calculation tabs.

Section 5Direct pay (§6417) for public-sector and tax-exempt buyers

For a municipality, school district, tribal government or non-profit building a 2026-start project of 1 MWac or more, Domestic Content is not a bonus. Without it — or a documented exception — the direct payment is zero.

5.1 The haircut schedule

Under §45Y(g)(12), applied to §48E through §48E(d)(5), the elective-payment "applicable percentage" is 100% if the facility meets Domestic Content or has a maximum net output under 1 MWac. Otherwise the percentage steps down by construction-start year: 90% for 2024 starts, 85% for 2025 starts and 0% for facilities that begin construction after 31 December 2025.

Chart 11 · Direct pay

The direct-pay haircut reached zero for 2026 starts

Elective-payment applicable percentage for facilities of 1 MWac or more that do not meet Domestic Content and claim no exception

5.2 The two exceptions

The statute sets the applicable percentage back to 100% if either exception applies:

• Increased cost: using domestic steel, iron or manufactured products would increase the overall cost of construction of the facility by more than 25%.
• Non-availability: the relevant products are not produced in the United States in sufficient and reasonably available quantities or of a satisfactory quality.

Notice 2024-84 extended the attestation route originally set out in Notice 2024-9. The applicable entity attests, under penalties of perjury, that it reviewed both exceptions and made a good-faith determination that one applies. The attestation must be signed by a person with authority to bind the entity in federal tax matters, attached to Form 3468 (or Form 8835), and supported by records kept under §6001. The route is available for facilities that begin construction before the later of 1 January 2027 or the date of further guidance.

5.3 Illustrative outcome

Illustrative, SolarStock USA Research, applying 26 U.S.C. §45Y(g)(12) and Notice 2024-84. Facility sizes are hypothetical. MACR must be met in every case for the credit to exist at all.

5.4 Other direct-pay considerations

• Pre-filing registration. Elective payment (and transfer) requires an IRS pre-filing registration number, which goes into the Domestic Content certification and the audit file.
• Excessive payments. Under §6417(d)(6), an excessive direct payment must be repaid with a 20% addition unless reasonable cause applies; the provision now explicitly covers excessive payments arising from a MACR disallowance.
• The MACR still applies. A tax-exempt entity is not exempt from the material-assistance test. A failed MACR means no credit, and therefore no direct payment.
• Transfer is not a workaround. Taxable owners can sell credits under §6418, but transfers to specified foreign entities are prohibited, and an excessive credit transfer is recaptured from the transferee with a 20% addition.

Section 6The playbook: from RFQ to tax return

Domestic Content is certified as of the placed-in-service date, and MACR is tested on the producer's status in the year of payment. Evidence created after delivery is weaker than evidence collected at the purchase order. The sequence below front-loads it.

Chart 12 · Process

Eleven steps, five owners

RFQ-to-return sequence for a 1–20 MW project, by responsible function

6.1 The steps that most often fail

Step 3 — scoring bids on price alone. A module that is cheaper per watt but has imported glass and backsheet can cost the project the bonus entirely (Section 4.6). The scenario workbook should run both tests on every short-listed bid.

Step 4 — contracts without change control. Substitutions are the single largest source of as-built divergence. A supplier that swaps a cell source or a factory mid-delivery can move a project from 51.8% to 23.1% without anyone in procurement noticing. The supply agreement should prohibit substitution without written consent and require re-issued certifications if one occurs.

Step 6 — collecting certifications after payment. Because PFE status is tested for the producer's taxable year that includes the payment date, a certification dated in a later year may not speak to the right period. Make the certification a condition of payment.

Step 8 — certifying the design BOM rather than the as-built BOM. Domestic Content is certified as of placed in service. The final calculation must reconcile POs, invoices, delivery documents and the change log.

Section 7Supplier vetting

The supplier questionnaire is the backbone of both tests. It gathers origin data for Domestic Content and ownership, control and producer data for MACR, and it puts suppliers on notice that their answers will be relied on.

7.1 Who to vet, and when

Every supplier of a manufactured product or MPC on the applicable table should complete the questionnaire: modules, inverters or MLPE, trackers or racking. Suppliers of structural steel should complete the steel section. Issue it with the RFQ, refresh it at purchase order and again at delivery. Where the seller is a reseller or holds inventory, ask for the identity of the manufacturer of each item — the PFE test looks to the entity that produced the item, not the seller.

7.2 Template A — Supplier vetting questionnaire

SolarStock USA Research template based on P.L. 119-21 (§7701(a)(51)–(52)); IRS Notices 2023-38, 2025-08, 2026-15; Connecticut Green Bank, Exhibit C FEOC Certificate – Module (Jun 2026).

7.3 Red flags

SolarStock USA Research, based on Notice 2025-08 §8.03, Notice 2026-15 §§3.01, 4.03, 5.01–5.02.

Practitioners caution that supplier attestations alone amount to a desktop exercise for FEOC purposes. Recommended additions include ownership mapping, screening against the relevant entity lists, a review of debt holders, and third-party chain-of-custody checks for high-risk components such as cells and wafers (pv magazine USA, 25 Feb 2026).

Section 8Manufacturer letters: compliant versus deficient

Most buyers receive a "domestic content letter" or a "non-PFE letter" from their module supplier. These documents vary widely. Some are certifications built to the statutory standard; many are marketing summaries that expressly disclaim reliance.

8.1 Two different documents

For MACR, the statute and Notice 2026-15 prescribe what a supplier certification must contain if the taxpayer wants the Certification Safe Harbor. For Domestic Content, there is no prescribed supplier form. The taxpayer certifies compliance itself; a manufacturer's letter is evidence supporting that certification, alongside origin documentation.

8.2 What a compliant MACR certification must contain

• The supplier's EIN, or a foreign-government taxpayer identification number.
• Signature under penalties of perjury.
• A commitment that the supplier will retain the certification for at least six years and produce it to the IRS on request; the taxpayer must retain it too.
• Issued by the supplier from whom the taxpayer actually purchased the item.
• Either (a) a statement that the item was not produced by a PFE and that the supplier does not know or have reason to know of any PFE in the prior supply chain, or (b) the total direct costs to the taxpayer that were not produced by a PFE.
• Attached to Form 3468 (or Form 7211 / 7207) for the first year of the credit claim.

§7701(a)(52)(D)(iii)(IV); Notice 2026-15 §4.03(2).

Two further rules apply. If the taxpayer knows or has reason to know that an item was PFE-produced, all of its costs are PFE costs, and a certification known to be inaccurate cannot be relied on. And the supplier is exposed to the §6695B penalty for inaccurate certifications provided after 31 December 2025.

8.3 What a strong Domestic Content letter usually contains

Because no IRS format exists, the following list is a synthesis of documents in circulation and is not a legal standard:

• Product models or SKUs, and serial or lot ranges covered.
• Factory address where the manufacturing process is performed.
• Each listed MPC with its manufacturer and country of manufacture.
• Cell and wafer origin, stated separately.
• The Notice 2025-08 table and column applied, and the percentage claimed, row by row.
• Effective date and validity period.
• Signer's name and authority.
• Reliance language — or, where the manufacturer disclaims reliance, that fact clearly stated.

8.4 Common deficient letters

A published manufacturer letter we reviewed illustrates the gap. It stated that a third-party review had verified the company's non-PFE status and that the manufacturer had received non-PFE certifications from its own suppliers. It presented a per-component table using the Notice 2025-08 columns, in which only the cells and the module "Production" row carried a percentage and every other listed module component was shown at zero, giving a total for each project type. The letter expressly disclaimed being tax advice or a certification for tax purposes and said it could not be relied on to determine eligibility. It carried no EIN and no penalties-of-perjury statement.

Several lessons follow for the buyer:

• It is not a MACR certification. Without an EIN, a perjury statement and a retention undertaking, it cannot support the Certification Safe Harbor, however accurate its content.
• Know which test a table speaks to. A table built for the PFE question does not answer the Domestic Content question. If a buyer wanted to use such a table as Domestic Content evidence, it would need to confirm the U.S. origin of every listed module component: under Notice 2025-08, the Production share counts only if all listed module MPCs are U.S.-produced.
• The disclaimer shifts the burden back to the taxpayer. The buyer must build independent evidence and, for MACR, obtain a certification from its direct supplier that meets the statutory form.

SolarStock USA Research review of manufacturer letters and of Connecticut Green Bank's Exhibit C FEOC Certificate – Module (Jun 2026); statutory content from §7701(a)(52)(D)(iii)(IV) and Notice 2026-15 §4.03.

8.5 A buyer-drafted model

Some public buyers have stopped accepting supplier-drafted letters. The Connecticut Green Bank's module FEOC certificate (June 2026) is a buyer-drafted template that the seller completes. It asks for the seller's EIN, PO number and date, and a component table showing description, quantity, total direct costs per the Notice 2025-08 (or later) tables, country of origin and PFE status. The seller represents that it is the direct supplier, that the goods are not PFE-produced, and that it knows of no PFE involvement down to cells, wafers, polysilicon and the main module materials. The template adds reliance by the buyer, its affiliates, lenders, tax equity and auditors; a cooperation and records duty; an eight-year retention period; consent to disclosure to Treasury and the IRS; and signature by an authorized officer under penalties of perjury. Mid-market buyers can adapt this model with counsel.

Section 9The audit-ready documentation file

An audit-ready file answers three questions without anyone having to reconstruct anything: what was installed, where each listed item came from and who made it, and who signed what on which date.

9.1 The taxpayer's own certification

A Domestic Content Certification Statement is required for each applicable project and is attached to Form 3468 (ITC) or Form 8835 / 7211 (PTC) for the first year the bonus is claimed; for PTC claims, a copy is attached every year of the credit period. Under Notice 2023-38 it states the project type, specific type, geographic coordinates and address, placed-in-service date and total bonus amount, and it is signed under penalties of perjury by a person with legal authority to bind the taxpayer. The 2025 Form 3468 instructions add the facility description, owner, IRS registration number where applicable, a statement that steel, iron and manufactured products were U.S.-produced under 49 CFR 661, and a statement if the elective safe harbor is relied on. The bonus is claimed by checking box 9a or 9b on Line 9; box 9c indicates no bonus. Compliance is certified as of the placed-in-service date.

9.2 Template B — Document checklist

SolarStock USA Research template based on IRS Notices 2023-38, 2024-84, 2025-08, 2026-15 and the 2025 Form 3468 instructions. For adaptation by counsel.

9.3 One workbook, two tests

The most efficient pattern is a single BOM register with one row per listed APC / MPC and, for each, the producer's legal name, factory location, country of manufacture, PFE status in the payment year, evidence reference, and delivery quantities. Two calculation tabs then read from it: one applies the Domestic Content conventions (unused rows at zero; Production conditional; steel/iron tested separately), the other the MACR conventions (unused rows and steel/iron disregarded; de minimis if elected). Because the producer and the country of manufacture are different facts, the register should never collapse them into a single "origin" field.

Section 10Record retention, penalties and exposure

The Domestic Content regime itself carries no special penalty. The MACR regime does — and for 2026-start projects, both sit in the same return.

10.1 How long to keep records

For Domestic Content, the general §6001 rule applies: records must be kept for as long as they may be material. Neither Notice 2023-38 nor Notice 2025-08 sets a fixed number of years. For MACR, supplier certifications must be retained by both supplier and taxpayer for at least six years, and the IRS has six years from filing to assess deficiencies arising from MACR errors under §6501(o).

A practical retention rule for mid-market buyers is the later of six years after filing the return that first claims the credit and the end of the period in which the records may become material. Recapture periods may extend that further: under §50(a)(1) the general investment-credit recapture period is five full years from placed in service, with the recapture percentage stepping down from 100% in year one by 20 points a year (100/80/60/40/20), and this applies to §48E property. For §48E property, the separate 10-year §50(a)(4) window for payments to prohibited foreign entities (below) is the longer horizon.

10.2 Penalty and exposure map

Notice 2026-15 §2.03; 26 U.S.C. §§50(a)(1), 6417(d)(6), 6418(g)(2); P.L. 119-21 §70513(b)(3); Notice 2023-38; draft 2026 Instructions for Form 3468. Under §50(a)(4), a specified taxpayer is one allowed a §48E credit for tax years beginning after 4 Jul 2027.

10.3 What this means for a 1–20 MW buyer

The 1% threshold changes the economics of error. On a mid-market project, a disallowed credit will almost always exceed 1% of the taxpayer's correct tax, so any MACR overstatement that leads to disallowance is likely to attract the 20% penalty unless reasonable cause can be shown. The best evidence of reasonable cause is a contemporaneous file: questionnaires issued before purchase, certifications dated at payment, a red-flag log, and a signed calculation. For transfer buyers, the 20% addition falls on the transferee, which is why credit purchasers increasingly ask for the full supplier file during diligence.

Section 11The U.S. manufacturing landscape and sourcing in practice

The arithmetic in Section 4 shows that U.S. cells are the decisive input. The supply picture in October 2026 is one of ample U.S. module assembly and still-thin U.S. cell output, with substantial cell capacity scheduled to come online through 2027.

11.1 The module–cell gap

SEIA's Q3 2026 Solar Market Insight puts U.S. module nameplate capacity at about 66 GWdc; a June 2026 report citing SEIA gave 69.9 GW, so published figures differ. By contrast, Wood Mackenzie estimated U.S. operational cell capacity at about 3 GW earlier in 2026 and expects it to reach 20.5 GW by the end of 2027. Nameplate is not output, and cell capacity under construction is not yet supply.

Chart 13 · Supply

U.S. module assembly far outstrips U.S. cell capacity

Reported U.S. nameplate capacity, module versus cell (GWdc per year)

11.2 Selected U.S. factories, October 2026

The table lists only facilities whose details we could source during this research cycle. Capacities are nameplate as reported by the named source, not production. It is not a complete census of U.S. manufacturing.

pv magazine USA (9 Jun, 10 Jul, 24 Jul 2026); pv magazine (8 Jul 2026); Business Wire (14 Apr 2026); HSC / PV Tech (13 Nov 2025); Utility Dive (11 Mar 2025); TaiyangNews (14 May 2026); PV Tech (14 Aug 2026); T1 Energy G2_Austin page; Hanwha/Qcells press release (11 Jun 2026); Solar Power World (9 Jun 2026); pv magazine (24 Jan 2025); Mercom (15 Apr 2025); Manufacturing Dive (26 Mar 2025); pv magazine USA (21 Mar 2025); GreenLancer (8 Oct 2026); York County SC (4 Aug 2026); Solar Power World via Now.Solar (30 Sep 2026); Solar Power World (Mar 2026); Solar Builder (2 Jun 2025); Heliene product information (Oct 2025). n/d = not disclosed in the sources read; n/c = not confirmed in public sources as of 14 Oct 2026. Inclusion does not imply that any product meets Domestic Content or MACR requirements.

Chart 14 · Cell capacity

U.S. cell capacity: operating, ramping and planned

Reported nameplate cell capacity by facility, October 2026 (GW)

11.3 What the landscape means for a 1–20 MW buyer

• Module assembly is not the constraint; cells are. A U.S.-assembled module with imported cells is widely available but, as Section 4 shows, contributes at most about 23% on a tracker project and 32.6% on a fixed-tilt project.
• Domestic cells are contracted early. Much of the U.S. cell and wafer capacity that is running is tied to integrated or long-term offtake arrangements. Mid-market buyers should expect to ask early and to receive allocation rather than spot availability.
• Thin-film follows different rows. The DCW columns are defined for c-Si cells. Buyers considering CdTe modules should rely on the manufacturer's own row mapping rather than extrapolate from c-Si arithmetic.
• Trade measures will reprice imports. From 4 December 2026, the §232 minimum import prices of $0.22/W for cells and $0.38/W for modules apply in addition to existing AD/CVD duties. For context, Anza reported a median U.S.-assembled module price of $0.30/W in data released in July 2026.

11.4 Sourcing DC-eligible modules in practice

In practice, sourcing for Domestic Content means sourcing evidence as much as hardware. A module's country of assembly is the starting point, not the answer. The buyer needs, for each candidate module: the cell manufacturer and factory; the wafer origin; the origin of every other listed MPC; a factory address for the manufacturing process; and a supplier willing to issue a MACR certification to the statutory standard.

U.S.-assembled modules are available through several channels, including manufacturers' direct sales teams and inventory platforms. SolarStock USA's platform, for example, lists U.S.-assembled modules among its inventory, including Sunpro Power modules assembled in Georgia. U.S. assembly alone does not establish Domestic Content qualification or MACR compliance. Nothing in this guide states or implies that any product available on SolarStock USA's platform qualifies for the Domestic Content bonus or meets the MACR threshold; that determination depends on the full bill of materials, the supplier documentation described in Sections 7 and 8, and the buyer's own certification.

Section 12Decision matrix for 1–20 MW buyers

The right Domestic Content strategy depends on four facts: AC size, PWA status, credit monetization route and mounting type. The matrix below is a SolarStock USA Research assessment, not tax advice.

12.1 Should we pursue the Domestic Content bonus?

SolarStock USA Research assessment. Criteria: bonus rates per §48(a)(12); direct-pay applicable percentage per §45Y(g)(12); MACR required for all 2026+ starts per §48E(b). Not tax advice.

12.2 Which BOM strategy?

Computed by SolarStock USA Research from IRS Notice 2025-08 §§5.05–5.06 (see Section 4.5). Maximums assume full documentation of every counted row. The 2027 threshold is 55%.

12.3 MACR is not optional

Whatever the Domestic Content decision, every 2026-start project must pass MACR. Notice 2026-15's Example 1 shows that a project whose only PFE-produced item is the cell can still reach 61.8%. The practical risk for mid-market buyers is therefore less the ratio itself than the evidence: identifying the producer of every listed item, testing its status in the payment year, and holding certifications that meet the statutory form.

Section 13Open questions: what to watch, Q4 2026 to 2027

The rules for 2026 starts are stable. The rules for 2027 starts are not. These are the items we are tracking.

SolarStock USA Research; McGuireWoods (6 Mar 2026); SEIA Solar Market Insight Q3 2026; Clifford Chance (4 Sep 2026); IRS draft 2026 Form 3468 and instructions; Troutman (FCC); Notice 2025-08; Notice 2026-15; Notice 2024-84.

Section 14Methodology, Sources & Disclosures

Methodology

This guide reflects law, guidance and market information available to the SolarStock USA Research Desk as of 14 October 2026. Primary texts — IRS Notices 2023-38, 2024-9, 2024-41, 2024-84, 2025-08, 2025-42 and 2026-15; P.L. 119-21; current text of 26 U.S.C. §§45, 45Y, 48, 48E, 6417 and 6418; the 2025 Instructions for Form 3468; and IRS web guidance on Domestic Content and elective pay — were read in full or in the relevant parts. We scanned the full text of Internal Revenue Bulletins 2026-02 through 2026-42 for Domestic Content, material-assistance, PFE and beginning-of-construction guidance, and queried the Federal Register API for IRS documents published since 1 January 2026.

The Notice 2025-08 cost-percentage tables were extracted from the notice PDF and each column was checked to sum to 100.0. Component subtotals and scenario percentages in Sections 4 and 12 are SolarStock USA Research computations on those tables; the tracking-column subtotals were cross-checked against Notice 2026-15 Example 1. Court developments, trade measures, factory data and market figures rely on the named secondary sources. Where sources conflict, both figures are shown.

Sources

Primary regulatory

• Public Law 119-21 (One Big Beautiful Bill Act), 139 Stat. 72, 4 Jul 2025 — govinfo.gov
• 26 U.S.C. §§45, 45Y, 48, 48E, 6417, 6418 — Cornell Legal Information Institute (accessed 14 Oct 2026)
• IRS Notice 2023-38 (12 May 2023), 2023-22 I.R.B. 872 — irs.gov/pub/irs-drop/n-23-38.pdf
• IRS Notice 2024-9 — irs.gov/pub/irs-drop/n-24-09.pdf
• IRS Notice 2024-41 (May 2024, corrected 24 May 2024), 2024-24 I.R.B. 1615 — irs.gov/pub/irs-drop/n-24-41.pdf
• IRS Notice 2024-84 — irs.gov/pub/irs-drop/n-24-84.pdf
• IRS Notice 2025-08 (16 Jan 2025), 2025-8 I.R.B. 800 — irs.gov/pub/irs-drop/n-25-08.pdf
• IRS Notice 2025-42 (15 Aug 2025) — irs.gov/pub/irs-drop/n-25-42.pdf
• IRS Notice 2026-15 (12 Feb 2026), 2026-11 I.R.B. 658; IR-2026-23 — irs.gov/pub/irs-drop/n-26-15.pdf
• IRS Notices 2026-37 and 2026-39 (cross-references) — IRBs 2026-26 and 2026-27
• Internal Revenue Bulletins 2026-02 through 2026-42 (IRBs 2026-37 to 2026-42 re-scanned 14 Oct 2026) — irs.gov/pub/irs-irbs
• IRS, Instructions for Form 3468 (2025), last reviewed 28 Aug 2026 — irs.gov/instructions/i3468
• IRS, Form 3468 (2026), early-release draft (created 27 Jul 2026) — irs.gov/pub/irs-dft/f3468--dft.pdf
• IRS, Instructions for Form 3468 (2026), early-release draft (15 Sep 2026) — irs.gov/pub/irs-dft/i3468--dft.pdf
• 26 U.S.C. §50(a)(1) and (a)(4) — Cornell Legal Information Institute (accessed 14 Oct 2026)
• IRS, Domestic content bonus credit (updated 23 Jan 2026) — irs.gov/credits-deductions/domestic-content-bonus-credit
• IRS, Elective pay FAQs (updated 7 Mar 2026) — irs.gov
• Federal Register API, IRS documents since 1 Jan 2026, including 1 Sep–14 Oct 2026 (queried 14 Oct 2026) — federalregister.gov

Legal & tax analysis

• Clifford Chance, "IRS Notice 2025-42 Appeal Deadline Nears", 4 Sep 2026
• go-alliant, "Notice 2025-42 Is Vacated…", 13 Aug 2026
• Troutman Pepper Locke, "District Court Vacates IRS Notice 2025-42…", 12 Jun 2026
• Miller & Chevalier, federal district court vacates IRS notice on wind and solar beginning of construction, 10 Jul 2026
• Plante Moran, "IRS Notice 2025-42 vacated", 9 Jun 2026
• Morgan Lewis / Law360, solar and wind credits after safe harbor revived, 15 Jun 2026
• Mayer Brown, interim guidance on material assistance (Notice 2026-15), 25 Feb 2026
• KPMG TaxNewsFlash, Notice 2026-15, Feb 2026
• McGuireWoods, initial FEOC guidance, 6 Mar 2026
• Clean Energy Counsel, Notice 2026-15 and interim safe harbors, 2026
• Hunton Andrews Kurth, §232 tariffs and minimum import prices on polysilicon and solar products, 11 Aug 2026
• Wiley Rein, §232 tariffs and minimum import prices on polysilicon and derivatives, 7 Aug 2026
• Troutman Pepper Locke, FCC bars foreign-produced power inverters, 2026

Market data

• SEIA / Wood Mackenzie, Solar Market Insight Q3 2026, 10 Sep 2026
• pv magazine USA, U.S.-assembled module prices (Anza data) and Illuminate USA stake, 10 Jul 2026
• pv magazine, U.S. cell capacity and ES Foundry expansion, 8 Jul 2026
• Cumulant, "The Cliff That Moved", 5 Jul 2026 (citing Wood Mackenzie)

Industry

• pv magazine USA, Qcells Cartersville cell production, 9 Jun 2026
• pv magazine USA, Canadian Solar subsidiary opens Indiana cell factory, 24 Jul 2026
• Business Wire, Suniva announces South Carolina cell facility, 14 Apr 2026
• TaiyangNews, T1 Energy Q1 2026 results, 14 May 2026
• PV Tech, "T1 Energy reports US$250 million Q2 sales", 14 Aug 2026
• T1 Energy, G2_Austin factory page (accessed Oct 2026)
• Hanwha / Qcells, press release on Cartersville cell manufacturing, 11 Jun 2026
• Solar Power World, Qcells starts production of solar cells in the United States, 9 Jun 2026
• pv magazine USA, Corning–T1 Energy supply agreement, 15 Aug 2025
• HSC / PV Tech, Corning U.S. wafer supply, 13 Nov 2025
• Utility Dive, Corning, Suniva, Heliene and Hemlock supply chain, 11 Mar 2025
• GreenLancer, U.S.-manufactured solar panels (8 Oct 2026) and domestic content requirements (24 Sep 2026)
• York County, SC, information on Silfab Solar (updated 4 Aug 2026)
• Solar Power World via Now.Solar, Silfab Fort Mill commissioning, 30 Sep 2026
• Solar Power World, "What's next for First Solar", Mar 2026
• Solar Builder, Meyer Burger closes Arizona site, 2 Jun 2025
• pv magazine, "Waaree's 1.6 GW solar factory in Texas starts commercial production", 24 Jan 2025
• Mercom, Waaree to double Texas module capacity to 3.2 GW, 15 Apr 2025
• Manufacturing Dive, OCI Holdings / Mission Solar Energy cell expansion in San Antonio, 26 Mar 2025
• pv magazine USA, Mission Solar announces 2 GW cell manufacturing in Texas, 21 Mar 2025
• Heliene product information sheet, Oct 2025
• Connecticut Green Bank, Exhibit C FEOC Certificate – Module, Jun 2026
• SolarEdge, domestic content guide for solar developers (blog), Nov 2025
• pv magazine USA, "Supplier attestations alone won't satisfy FEOC scrutiny", 25 Feb 2026
• Manufacturer Domestic Content and non-PFE letters reviewed by SolarStock USA Research (not individually cited)

Limitations & assumptions

• The status of Oregon Environmental Council v. IRS is based on published practitioner reports (Clifford Chance, 4 September 2026) and on IRS and Federal Register publications through 14 October 2026; we did not review the court docket directly.
• Draft 2026 versions of Form 3468 (27 July 2026) and its instructions (15 September 2026) were reviewed; final versions had not been released as of 14 October 2026.
• Factory capacities are nameplate figures as reported by third parties and may not reflect output, allocation or availability. The factory table is selective, not a census.
• Scenario percentages are maximums that assume every counted row is documented as U.S.-made; real BOMs typically score lower.
• Illustrative calculations use hypothetical basis values and facility sizes and do not represent any actual project, product or price.
• Manufacturer statements were read as published and were not audited.
• Guidance is interim in several areas (Notice 2026-15) and may change with MACR tables, proposed regulations or court action.

About SolarStock USA Research

SolarStock USA Research is the analytical desk of SolarStock USA, the first live-inventory solar module platform in the United States, operated by Yulz Design LLC. SolarStock USA holds Tier 1 manufacturers' module inventory in U.S. warehouses in California, Georgia, New Jersey and Texas, with brands including Sunpro Power, JA Solar, Mission Solar, Waaree and ZN Shine. Research outputs reflect the desk's independent analytical view; they are not investment advice and do not constitute a solicitation.

About the Authors

Yuliani Llohis is the Founder and Chief Executive Officer of SolarStock USA. Previously, she built and led Zytech Solar USA — the US subsidiary of Spanish PV manufacturer Zytech Solar Group — for fifteen years, with full P&L responsibility for the American market across residential, commercial, and utility-scale segments. The SolarStock USA Research Desk synthesizes primary regulatory sources, third-party market data and manufacturer documentation into published research.

Disclosure

SolarStock USA sells solar modules, including U.S.-assembled products, and has a commercial interest in the market described in this guide. Brands available on its platform are named in the About section above. References to products or manufacturers are informational and do not state or imply that any product qualifies for the Domestic Content bonus, meets the MACR threshold or is free of PFE involvement.

Republication

Excerpts may be quoted with attribution to "SolarStock USA Research, Domestic Content Compliance Playbook for Mid-Market Procurement, Q4 2026 Edition". The templates in Sections 6, 7 and 9 may be adapted for internal use with counsel's review. Charts and tables may not be republished in full without written permission.