When underwriting affordable housing projects using the 4% Low-Income Housing Tax Credit (LIHTC) paired with tax-exempt bond financing, one of the key hurdles developers and investors face is the bond volume constraint. Specifically, the "25% bond test" plays a pivotal role in both deal feasibility and tax planning strategy. Understanding how this bond test interacts with available tax deductions—especially permanent 100% bonus depreciation—and other accelerated depreciation options can mean the difference between a solid underwriting model and one that falls short.
What Is the 25% Bond Test in 4% LIHTC Financing?
Under the 4% LIHTC program, a key requirement is that at least 50% of the project's reasonably expected basis must be financed by tax-exempt private activity bonds. The maximum tax-exempt bond amount is constrained by the volume cap assigned to each state and other factors. To qualify for the 4% credit, the project must pass what’s commonly referred to as the “25% bond test,” meaning at least 25% of the project's total reasonably expected basis is financed with tax-exempt bonds.
When developers can meet this 25% threshold, it unlocks access to lower-cost capital and allows stacking of credits more easily, which improves project cash flow and underwriting results. But Learn here why does that matter from a tax depreciation standpoint? Because the presence of tax-exempt bonds triggers certain IRS rules that can affect depreciation deductions and eligibility for bonus depreciation.
Permanent 100% Bonus Depreciation and Timing Rules
Since the Tax Cuts and Jobs Act of 2017 (TCJA), 100% bonus depreciation is available for qualified property placed in service after September 27, 2017. This permanent benefit allows taxpayers to immediately expense the full cost of eligible tangible personal property and certain building components instead of capitalizing them and depreciating over many years.
For 4% LIHTC deals financed with tax-exempt bonds, however, bonus depreciation must be navigated carefully. IRS rules disallow bonus depreciation for property financed by tax-exempt obligations—except under certain situations where the "private use" of the property exists. Thus, when at least 25% of the project is financed by tax-exempt bonds, the ability to use bonus depreciation on components of the property is more constrained, as bond-financed property often disqualifies.
To make the numbers pencil out, savvy cost segregation studies (explained next) are essential to isolate components that can qualify for bonus depreciation despite bond financing. Timing also matters; property must be placed in service within the year to maximize bonus depreciation benefits. Deals targeting placed-in-service deadlines before year-end often run a quick sanity-check math on depreciation schedules to optimize deductions in year 1.
Key takeaway:
- 100% bonus depreciation applies only to property not financed by tax-exempt bonds unless private use applies. Placed-in-service date cutoffs are critical—property must be 100% ready and available in service within the tax year.
Cost Segregation and Shorter-Life Components
Cost segregation studies are a proven strategy in commercial real estate and affordable housing to accelerate depreciation deductions. By breaking down the building components into classifications with shorter recovery periods (5, 7, or 15 years instead of 27.5 or 39 years residential/commercial property), investors can shift expenses forward and increase early tax benefits.
For 4% LIHTC projects with bond financing, cost segregation helps identify personal property and land improvements that are not financed by bonds or where private use exists, enabling use of bonus depreciation or shorter alternative depreciation system (ADS) classes.
Examples of typical shorter-life components include:
- Appliances, carpeting, and cabinetry (personal property – 5 or 7 years) Site improvements like landscaping, sidewalks, and fences (land improvements – 15 years) Qualified production property components, if any (see next section)
In affordable housing underwriting, incorporating a detailed cost segregation study upfront ensures the project's depreciation schedule aligns with both timing rules and the bond volume constraint. It provides a clear map of which components qualify for accelerated write-offs and which must be depreciated over standard life due to bond restrictions.
Qualified Production Property (Section 168(n)) and Manufacturing Activities
Although 4% LIHTC projects are primarily residential rental housing, some developments may include elements considered Qualified Production Property (QPP) under Section 168(n), such as on-site manufacturing or certain special building components used in producing tangible personal property. If these components exist and meet IRS criteria, they can qualify for a 15-year recovery period and 100% bonus depreciation.
This designation is valuable because it accelerates deductions even on bond-financed property, provided the production use is evidenced and isolated from the bond financing allocation.
However, in most affordable housing deals—especially those primarily residential—QPP opportunities are limited or nonexistent. Therefore, developers should carefully evaluate whether special uses or ancillary manufacturing qualify under Section 168(n) to maximize depreciation benefits.
Section 179 Expensing: Larger Limits and Phaseouts
Section 179 allows taxpayers to immediately expense certain qualifying property rather than capitalizing and depreciating it. As of recent years, Section 179 limits have increased substantially, partially due to inflation adjustments. The benefit phaseouts begin once total acquired property exceeds certain thresholds.
In 4% LIHTC projects under bond financing, Section 179 is typically less helpful because bond-distributed property generally doesn’t qualify. Nevertheless, personal property components acquired separately—which are not bond-financed—may be expensed under Section 179. Larger limits (currently over $1 million annually in qualifying property) make it feasible to expense substantial amounts in the acquisition year, improving cash flows for passive investors.
The phaseout rules also mean developers need to do quick deal checklists upfront to estimate the aggregate property acquisitions within the tax year. Exceeding thresholds will reduce the Section 179 expensing option, so managing acquisition timing can preserve maximum immediate deductions.
How the 25% Bond Test Impacts Affordable Housing Underwriting
From an underwriting perspective, the bond volume constraint and the 25% bond test shape the capital stack, tax strategies, and ultimately the project's financial viability:
Lower Interest Costs but Limited Depreciation: Tax-exempt bonds bring cheaper debt but restrict bonus depreciation on bond-financed property, reducing immediate tax shields. Cost Seg Studies Critical: Separating assets into bond and non-bond financed pools allows for tactical depreciation acceleration strategies and accurate cash flow projections. Timing and Placed-in-Service Planning: Early placed-in-service dates maximize first-year bonus depreciation opportunities; pushing past year-end misses this. Section 179 and QPP Relationships: Although these can boost deductions, their impact is often limited by bond financing unless ancillary uses justify qualification. Item Rule or Limit Implication for 4% LIHTC Deals 25% Bond Financing Threshold ≥25% of basis financed by tax-exempt bonds Qualifies project for 4% LIHTC, unlocks cheaper debt, limits bonus depreciation on bond-financed property Bonus Depreciation 100% for property placed in service after 9/27/2017; disallowed for tax-exempt bond-financed property unless private use applies Requires segregation of property and precise placed-in-service timing Cost Segregation Allows identification of personal property and land improvements with shorter recovery periods Improves tax efficiency despite bond financing constraints Qualified Production Property (Section 168(n)) 15-year recovery, bonus eligible for manufacturing components Usually limited in affordable housing but valuable if applicable Section 179 Expensing Limits exceeding $1 million property acquisition phase out deductions Helpful mainly for non-bond financed personal propertyConclusion: Navigating Bond Constraints to Maximize Tax Benefits in 4% LIHTC Deals
The "25% bond test" is more than just a financing metric—it's a central pivot point in structuring, underwriting, and tax planning for 4% LIHTC affordable housing projects. While access to tax-exempt bonds helps lower borrowing costs and facilitate credit compliance, the related tax depreciation impacts more info require careful scrutiny to avoid pitfalls.
Developers and investors who proactively incorporate cost segregation studies, evaluate potential qualified production components, and understand the nuances of permanent 100% bonus depreciation and Section 179 can unlock meaningful tax savings. Paying close attention to placed-in-service timing and bond volume allocation restrictions ensures conservative yet optimized underwriting.
Always perform a quick sanity-check math on anticipated deductions versus bond-financed amounts and placed-in-service deadlines to avoid surprises after closing. Only by integrating these tax-aware strategies into the deal underwriting process before closing can investors truly make 4% LIHTC deals pencil out in today's competitive affordable housing market.
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