What is tax equity in solar finance?
Tax equity monetizes the federal investment tax credit and depreciation. Partnership flips, sale-leasebacks, inverted leases, and Section 6418 transfers are the main tools.
Tax equity is one of the most important—and most misunderstood—components of the U.S. solar capital stack. For developers, investors, and advisors financing solar infrastructure, understanding how tax equity works is essential to structuring bankable projects and maximizing returns.
What is tax equity?
Solar projects generate valuable federal tax benefits, primarily the Investment Tax Credit (ITC) under Section 48E and accelerated depreciation under Section 168 (MACRS). Many project developers cannot fully use these benefits themselves because they lack sufficient tax liability.
Tax equity investors—typically large financial institutions with substantial tax appetite—provide capital in exchange for the right to monetize these benefits. This partnership allows the value of the incentives to flow to a party that can actually use them.
What are the main tax-equity structures (flip, sale-leaseback, inverted lease)?
Several structures allocate tax benefits and cash flows between parties:
- Partnership flip: the tax equity investor takes most benefits until reaching a target return, then the allocation "flips" to the sponsor
- Sale-leaseback: the sponsor sells the project and leases it back
- Inverted lease: used in specific circumstances to pass the ITC to a lessee
Each carries different accounting, risk, and return implications. The right structure depends on offtake terms, sponsor profile, and lender requirements—making bankable PPA design a prerequisite for competitive tax-equity terms.
How do Section 6418 transfers and T-flip hybrids work?
Since 2023, developers have also been able to sell federal credits directly to unrelated corporate buyers under Section 6418. The transfer election lets an eligible taxpayer sell all or a specified portion of an eligible credit—including the Section 48E investment credit—for cash, without relying solely on a tax-equity partner's own tax capacity.
A growing approach is the hybrid: a traditional partnership captures depreciation and any basis step-up, while the credit itself is transferred to a third-party buyer. These "T-flip" structures combine partnership economics with a much broader buyer pool.
How does the OBBBA change tax-equity diligence?
With the phase-out of the solar ITC under the One Big Beautiful Bill Act, credit-eligible projects—those with defensible beginning-of-construction positions or a clear path to a 2027 in-service date—carry embedded value that the shrinking eligible pipeline makes scarcer. Diligence on construction-start documentation and safe-harbor equipment spend is now a core part of every tax-equity and transfer negotiation.
How does tax equity change project returns?
Tax equity typically funds a meaningful share of a project's capital cost, reducing the amount of sponsor and cash equity required. Efficient tax-equity structuring can materially improve project-level and investor returns by converting credits and depreciation into cash at closing.
What do tax-equity investors require before they commit?
Tax equity investors conduct rigorous diligence. Bankable production estimates, creditworthy offtake, and sound legal structures—validated through institutional underwriting—are prerequisites for attracting competitive terms.
How Sunlight helps
Sunlight Energy Investments structures capital stacks, including project equity, tax equity, and debt, tailored around each project's economics. We position projects to attract the right capital partners and reach financial close.
To discuss project finance, explore our advisory services or contact us.
