Budget Reconciliation Law Puts Beginning of Construction in the Spotlight

On 4 July 2025, President Donald Trump signed the Republican budget reconciliation bill, known as the “One Big Beautiful Bill Act” (OBBBA), Pub. L. No. 119-21 into law. Consistent with past law, certain provisions in the legislation require a taxpayer to establish the beginning of construction (BOC) to qualify for tax credits and deductions. 1 For example, under the OBBBA, wind and solar facilities that begin construction after 4 July 2026 and are placed in service after 31 December 2027 cannot receive the Section 45Y or Section 48E credit; for the Section 45V credit, construction must begin by 31 December 2027. Rules requiring application of a material assistance cost ratio (MACR) generally apply to those facilities beginning construction after 31 December 2025. Eligibility for the new