The 5 percent safe harbor is back. The July 4 deadline is not moving.

Projects that establish beginning of construction by July 4, 2026 keep the full 30 percent investment tax credit and have until December 31, 2030 to come online. Projects that miss the date must be operating by December 31, 2027 or lose the credit entirely. For a $5 million project, that gap is roughly $1.5 million in after-tax value.

The court ruling is not settled law. The IRS can appeal and seek an emergency stay in the D.C. Circuit. The trial court itself noted there is “almost zero chance” of appellate resolution before July 4. The strategy that survives every outcome is to document both compliance paths in parallel.

What just happened

In Oregon Environmental Council v. IRS, the U.S. District Court for the District of Columbia vacated IRS Notice 2025-42 in full. That notice, issued in August 2025, had eliminated the 5 percent safe harbor for solar projects above 1.5 MW AC. With the notice vacated, the 5 percent path is restored for projects of every size, governed by the longstanding rules in Notice 2013-29 and Notice 2018-59.

The government has not yet appealed but is widely expected to. A successful emergency stay before July 4 would put the 5 percent safe harbor back in limbo for any project above 1.5 MW that had not already locked it in.

The deadline math

Two dates control the economics.

July 4, 2026 is the last day to establish beginning of construction. Projects that hit this date are subject to a 4-year continuity safe harbor and must be placed in service by December 31, 2030.

December 31, 2027 is the placed-in-service cliff for any project that misses the July 4 BOC date. There is no graduated phase-down. The credit goes from 30 percent to zero. Standalone battery storage is exempt from this cliff and retains its full ITC runway through 2033.

For a 2 MW ground-mount project carrying roughly $5 million in depreciable basis, missing July 4 means trading about $1.5 million in tax credit value for a 17-month construction sprint that most projects cannot meet.

The two methods owners should authorize in parallel

For accrual-basis owners, the 3.5-month rule in Treasury Regulation Section 1.461-4(d)(6)(ii) treats equipment as “incurred” at payment time if delivery is reasonably expected within roughly 105 days. A wire transfer on July 3 against an October 17 delivery date can satisfy the 5 percent test on a 2026 BOC.

Documenting both paths is not redundant. It is the only position that holds whether the IRS appeals, wins a stay, issues a new notice, or stands down.

Three project archetypes and the deposit math

The storage carve-out matters. Material Foreign Entity of Concern (FEOC) rules apply to both, but with asymmetric thresholds for 2026 starts: solar must keep prohibited-foreign content below 60 percent of direct manufacturing cost, while battery storage faces a tighter 45 percent ceiling. A supplier mix that clears the solar threshold may still fail for the BESS.

The traps that kill the credit at audit

1. Single-method reliance. Documenting only the 5 percent path leaves the project exposed if the IRS wins a stay. Documenting only physical work leaves it exposed if the contracting record is thin. The IRS audits the weaker of the two records.
2. Site clearing called physical work. Earthwork to clear vegetation, change contour, or rough-grade a site is explicitly excluded from physical work of a significant nature. Only excavation for a specific foundation, setting anchor bolts, and pouring concrete pads qualify.
3. Inventory components. The Physical Work Test requires components that are not normally held in inventory by the manufacturer. Standard-catalog modules pulled from a distributor warehouse satisfy the 5 percent dollar test but not the physical work test. Custom-spec or project-specific manufacturing is required.
4. Binding contract language with weak liquidated damages. A purchase agreement that caps damages below 5 percent of the contract price is not binding under the IRS rules. Standard distributor terms with $1,000 liquidated-damages clauses or deposit-only liability fail the test.
5. FEOC creep after BOC. A valid BOC in June 2026 does not protect a project from supplier substitution in 2027. The MACR threshold is measured at the qualified facility level, at completion. A module swap to a Chinese-controlled manufacturer after BOC can disqualify the credit.

What an owner should authorize in the next 21 days

1. Direct your developer to commit, in writing, to documenting both BOC methods in parallel.
2. Obtain written FEOC certifications from every module, inverter, and battery supplier in the bill of materials.
3. Confirm that any equipment purchase agreement contains a liquidated-damages clause of at least 5 percent of the contract price.
4. For solar plus storage projects, request a written technical memo explaining whether the BESS can operate independently of the solar facility.
5. Lock in a non-refundable equipment deposit equal to 7 to 8 percent of projected depreciable basis if the project is relying on the 5 percent path.
6. Require the developer to deliver a BOC documentation package suitable for tax-equity and lender diligence, not just internal files.
7. Set a calendar reminder for the IRS appellate docket. A stay motion will surface in the D.C. Circuit and will move fast if it is filed.

Five questions to bring to your tax counsel

1. Does our entity accounting method support the 3.5-month rule on a July 4 payment?
2. Will our project BOC documentation package satisfy our tax-equity partner diligence standards, not just IRS audit standards?
3. If the IRS obtains an appellate stay before July 4, does our physical work record stand independently?
4. For solar plus storage, are we treating the BESS as a separate Section 48E facility, and is the independent-operation memo in our file?
5. What is our supplier substitution protocol between BOC and placed-in-service to maintain MACR compliance?

Solara Pro is a commercial solar developer based in Broomfield, Colorado. This briefing is current as of June 13, 2026 and reflects guidance and case law in effect on that date. It is not legal or tax advice. Commercial owners considering an ITC-qualifying project should engage independent tax counsel and verify all positions against the IRS notices and the most recent court orders before committing capital. Solara Pro accepts no liability for decisions made without that review.