The LIHTC Capital Stack: Soft Debt, Deferred Developer Fee, and Gap Financing

Key Takeaways

Anatomy of the Capital Stack

A LIHTC deal does not have one source of capital. It has many. The Terner Center for Housing Innovation at UC Berkeley documented what practitioners already know from experience. In Kneebone and Reid's April 2021 report, The Complexity of Financing Low-Income Housing Tax Credit Housing in the United States, developers in a syndicator sample of properties built between 2000 and 2018 layered an average of 3.5 permanent sources, and one in four layered at least 5 (in some cases as many as 11). Each additional source introduces its own underwriting requirements, compliance obligations, and intercreditor dynamics, and the report cites earlier research on California 9% new construction that associated each one with roughly $6,500, or 1.7%, more in per-unit cost.

This complexity is structural, not optional. Tax credit equity, the largest single source in most deals, covers roughly 25-35% of total development cost in a 4% bond deal and 55-70% in a 9% deal. The remaining gap must be filled by some combination of hard debt, soft debt, and deferred developer fee. In a 4% bond deal, the gap is substantial.

Understanding the capital stack means understanding how each source is sized, what drives its terms, and how the sources interact with each other. A change in one source (a reduction in soft debt, a shift in credit pricing, a rise in interest rates) cascades through the entire stack.

Tax Credit Equity

Tax credit equity is the foundation of the capital stack. It is generated by the LIHTC credit calculation (eligible basis × applicable fraction × credit rate) and converted to equity when the developer sells the 10-year credit stream to an investor, typically through a syndicator.

How equity is sized

The equity amount is a function of three variables: the annual credit amount, the 10-year credit period, and the credit pricing. Credit pricing, the cents-per-dollar an investor pays for each dollar of tax credit, fluctuates with market conditions, deal quality, and investor demand. Syndicators quote it deal by deal, and trackers such as CohnReznick's monthly Housing Tax Credit Monitor report current pricing. The examples in this article use $0.85 per credit dollar as an illustrative assumption. Supply is also changing: for calendar years after 2025, OBBBA raised the per-capita and small-state minimum amounts behind each state housing credit ceiling (the competitive 9% pool) by 12%.

For a 9% deal, equity typically covers 55-70% of total development cost. For a 4% deal, equity covers 25-35%. This difference is the single biggest driver of capital stack complexity: 4% deals must fill a much larger gap with other sources.

Pay-in schedule

Investors don't write a single check at closing. Equity is paid in installments tied to construction and compliance milestones, such as closing, construction completion percentages, placed-in-service, stabilization, and 8609 delivery, with the split negotiated deal by deal. The gap between when the developer needs cash and when the investor pays in creates a bridge financing need, which adds another layer to the capital stack.

Hard Debt and Bond Financing

Hard debt in a LIHTC deal refers to conventional mortgage financing that is sized based on the project's net operating income and must be repaid from operating cash flow. It takes two primary forms:

Tax-exempt bonds (4% deals)

In a 4% deal, tax-exempt private activity bonds subject to the state volume cap are the primary debt instrument, and they are what make the 4% credits available without a competitive allocation. Under IRC 42(h)(4)(B), the bonds must finance at least 50% of the aggregate basis of the building and the land on which it is located. The 2025 One Big Beautiful Bill Act added a 25% alternative for buildings placed in service in taxable years beginning after December 31, 2025: it applies if bonds finance at least 25% of that aggregate basis and bonds that are part of an issue dated after December 31, 2025 finance at least 5% of it. Bonds are issued by a government entity (typically the state HFA or a local housing authority) and carry tax-exempt interest rates set by the municipal yield curve, the bond term, and whether the bonds carry credit enhancement or are privately placed with a single bank.

Bond sizing answers two different questions. The bond test sets a floor on total bond financing (50% of aggregate basis, or 25% where the new alternative applies). The debt service coverage ratio (NOI must cover annual debt service at 1.15-1.20x, depending on lender requirements) caps how much of that debt can stay outstanding as permanent financing. In practice, the DSCR constraint is usually the binding limit on permanent debt: the project's restricted rents generate limited NOI, which caps the supportable debt. When the bond test calls for more bond financing than NOI can carry, the excess is issued as short-term bonds and redeemed at conversion, typically from equity pay-ins.

Conventional permanent loan (9% deals)

In a 9% deal without bond financing, the permanent loan is a conventional mortgage, often an FHA-insured loan (Section 221(d)(4) for new construction or substantial rehabilitation; Section 223(f) for the purchase or refinancing of existing properties that do not need substantial rehabilitation; both administered by HUD's Office of Multifamily Housing) or a Freddie Mac/Fannie Mae product designed for affordable housing. These loans are sized to a DSCR of 1.15-1.25x with long amortization periods (Section 223(f) terms run up to 35 years). Fixed rates are quoted as a spread over the 10-year Treasury, which stood at 5.31% on October 5, 2026 (FRED, DGS10), so the all-in coupon moves with that benchmark.

Construction financing

During construction, the project uses a construction loan (or construction-period bonds) that converts to permanent financing at stabilization. Construction loan interest is typically capitalized and included in eligible basis. The construction loan is sized to cover total development cost minus equity pay-ins received during construction.

Soft Debt Sources

Soft debt is subordinate financing with below-market terms: low or zero interest, deferred payments, long maturities, or some combination. It fills the gap between what hard debt and tax credit equity can cover and the total development cost. In a 4% deal, soft debt typically represents 15-30% of the capital stack.

The term "soft" refers to the repayment terms, not the certainty of the commitment. Soft debt is real money from real sources with real compliance requirements. Here are the primary sources:

HOME Investment Partnerships Program

Federal block grant authorized under Title II of the Cranston-Gonzalez National Affordable Housing Act (42 USC 12721 et seq.) and awarded by HUD as formula grants to participating jurisdictions (states and units of general local government that qualify for an allocation). HOME funds for rental housing typically come as soft loans at low or zero interest with long terms and repayment from surplus cash flow. HUD publishes maximum per-unit subsidy limits annually (24 CFR 92.250). HOME has specific requirements: property standards, rent limits (which may differ from LIHTC limits under 24 CFR 92.252), income targeting (often 50% AMI vs LIHTC's 60%), and environmental review under 24 CFR Part 58.

Housing Trust Fund (HTF)

The National Housing Trust Fund, established by the Housing and Economic Recovery Act of 2008 (HERA), is funded by a statutory set-aside of 4.2 basis points on Fannie Mae's and Freddie Mac's new business purchases, 65% of which goes to the HTF (12 USC 4567). It targets extremely low-income households (30% AMI). HUD allocates HTF funds by formula to states, and states or state-designated entities (often the HFA) administer them; HOME, by contrast, flows to both state and local participating jurisdictions. HTF-assisted units must stay affordable for at least 30 years after project completion (24 CFR 93.302(d)), and loan terms are set by the grantee. The deep targeting requirement means HTF-funded units generate the lowest rents in the project, an important pro forma consideration.

CDBG (Community Development Block Grant)

Federal block grant that can be used for affordable housing in certain circumstances. Less common than HOME for LIHTC deals, but available in some jurisdictions. Terms are highly local: each grantee sets its own loan structure.

State and local housing trust funds

Many states and municipalities operate their own housing trust funds with dedicated revenue sources (real estate transfer taxes, document recording fees, general appropriations). Terms vary widely: some provide grants, others provide soft loans at low interest with long terms. These are often the most flexible sources in the stack, with fewer federal compliance requirements than HOME or HTF.

Federal Home Loan Bank Affordable Housing Program (AHP)

Competitive grants from the regional Federal Home Loan Bank, awarded through a competitive application scored on affordability depth, special populations served, and community impact. Each Bank may set its own maximum subsidy per member, per sponsor, per project, or per unit in its AHP Implementation Plan (12 CFR 1291.24(c)). AHP is a grant (not a loan) in most cases, but the application is competitive and the timing depends on each Bank's funding-round schedule.

Seller financing

In acquisition/rehab deals, the seller sometimes provides a soft take-back note as part of the transaction. This is most common in Year 15 resyndications where the existing limited partner exits and the general partner (or a new developer) acquires the property. Seller notes are typically structured with deferred payments and below-market interest to preserve cash flow for the new deal.

Intercreditor dynamics

Every soft debt source requires a subordination agreement with the senior lender. The senior lender (bondholder or permanent lender) holds the first mortgage and has priority in a foreclosure. Soft lenders agree to subordinate their liens, but many impose conditions: standstill agreements, notice requirements, cure rights, and restrictions on senior debt modifications. Negotiating intercreditor agreements across several soft lenders is one of the most time-consuming aspects of closing a LIHTC deal.

Deferred Developer Fee

The deferred developer fee is the residual gap-filler in most LIHTC deals. When tax credit equity, hard debt, and soft debt still don't cover total development cost, the developer defers a portion of their fee, agreeing to be paid from future cash flow rather than at closing.

How it works

The developer fee is a line item in the development budget, typically 10-15% of total development cost (excluding the fee itself and the land cost). State HFAs cap the fee in their qualified allocation plans or underwriting rules, and the formulas vary. Texas, for example, limits the developer fee included in eligible basis to 15% of the project's eligible costs, less the developer fee, for developments of 50 units or more, and 20% for 49 units or fewer (10 Tex. Admin. Code 11.302). The $3.3M fee in the worked example below is 13.5% of TDC excluding the fee and land ($24.5M), and 14.9% of its assumed eligible costs less the fee ($25.5M of eligible basis less $3.3M, or $22.2M), inside a 15% cap of the Texas type.

The "deferred" portion is the amount of the fee that is not paid at closing or during construction. Instead, the developer receives a promissory note from the project entity (the limited partnership or LLC) that is repaid from surplus cash flow: cash flow remaining after operating expenses, debt service, replacement reserve deposits, and asset management fees.

The 15-year repayment test

State HFAs and syndicators commonly require a reasonable expectation that the deferred developer fee can be repaid from cash flow within 15 years. Texas writes the test into its underwriting rules: an application is infeasible if the estimated deferred developer fee "is not repayable from Cash Flow within the first 15 years of the long term pro forma" (10 Tex. Admin. Code 11.302). This is a critical constraint: the pro forma must show sufficient surplus cash flow to repay the deferred fee within that window. If the cash flow projections don't support repayment, the deferred fee doesn't count as a credible financing source, and the deal has an unresolved gap.

Syndicators and investors scrutinize this projection carefully. Common points of contention: the assumed revenue growth rate (typically 2-3%), the assumed expense growth rate (typically 3-4%), and the assumed vacancy rate (typically 5-7%). Aggressive assumptions on any of these variables can produce a cash flow projection that appears to repay the deferred fee but won't in practice.

How much can be deferred

There is no hard federal cap on the percentage of the fee that can be deferred, but practical limits apply. Syndicators generally expect the developer to receive part of the fee at closing or during construction, because the developer needs cash to cover predevelopment costs, staff, and overhead. Deferring more than 50-60% of the fee creates investor concern about developer financial capacity and motivation to complete the project.

State HFAs have their own limits. Some states cap the deferred portion at 50% of the total fee. Others allow higher deferrals but require more aggressive cash flow projections to demonstrate repayment within 15 years.

Worked Example: Sources and Uses

The following example shows a complete sources and uses statement for a 100-unit, 4% bond deal in a mid-cost market. This is the format that state HFA applications, syndicator underwriting memos, and lender credit packages all expect. Credit pricing, loan terms, and operating figures are illustrative assumptions.

Uses of funds

Table 1. Uses of funds. Hard construction costs dominate at 62% of TDC. The developer fee (11% of TDC) is the primary candidate for deferral if a gap exists.

Sources of funds

Table 2. Sources of funds. Eight distinct sources, which puts this deal in the quarter of the Terner Center sample that layered at least 5. The deferred developer fee ($1.48M, or 45% of the total $3.3M fee) fills the residual gap. The developer receives $1.82M at closing and during construction and defers the rest.

This deal has eight funding sources. Each source requires its own application, underwriting, commitment letter, loan agreement, subordination agreement, and compliance reporting. The HOME funds require a federal environmental review. The AHP grant requires a separate competitive application to the Federal Home Loan Bank. The state and county housing trust funds have their own income targeting and reporting requirements. This is what practitioners mean when they describe LIHTC capital stacks as "layered."

The $11.0M permanent bond carries $666,188 of annual debt service. Against year-one NOI of $870,000 ($1,520,000 of effective gross income less $650,000 of operating expenses), that is 1.31x coverage, above the 1.15x minimum, which leaves surplus cash to repay the deferred fee (Figure 3). At the 1.15x minimum, the same NOI would support about $12.49M of permanent debt; the example holds the bond at $11.0M to keep a coverage cushion and surplus cash for the deferred fee, which is a judgment call rather than a rule. For the bond test, the aggregate basis of building and land is about $28.05M, assuming every line in Table 1 except reserves, syndication costs, and bond issuance costs is capitalized into the building or land. The 50% test would require at least $14.03M of bond financing, so about $3.03M of short-term bonds would be redeemed at conversion. If the building qualifies for the 25% alternative, the $11.0M permanent tranche alone (39% of aggregate basis) clears the $7.01M threshold, provided bonds from an issue dated after 2025 finance at least $1.40M (5%).

Common Mistakes

These are the errors that derail LIHTC capital stack underwriting most frequently:

• Treating the gap as a line item instead of a problem. A pro forma that shows "gap financing: $4,000,000" without identifying a specific source is not underwritten. Investors, HFAs, and lenders all need to see committed or highly probable sources for every dollar. An unresolved gap is a deal that isn't ready.
• Undersizing the deferred developer fee repayment period. The 15-year cash flow projection must use conservative assumptions. Revenue growth at 2% (not 3%), expense growth at 3-4%, vacancy at 7%. If the fee isn't fully repayable under these assumptions, either reduce the deferred amount or restructure the cash flow waterfall.
• Ignoring soft debt compliance stacking. Each soft source has its own income targeting, reporting, and inspection requirements. HOME may require 50% AMI targeting on funded units. HTF requires 30% AMI. The state trust fund may have different unit size standards. These requirements can conflict with each other and with LIHTC requirements. Map all compliance obligations before committing to a source.
• Failing to account for subordination timing. Intercreditor negotiations between senior lenders and several soft lenders can take months. If you assume simultaneous closing of all sources, you will miss your construction start date. Build subordination negotiation time into the development schedule.
• Using stale credit pricing. Credit pricing moves with investor demand, and last year's LOI may no longer hold. A 6-cent move on $10M in credits is $600,000 in lost equity, which must be replaced by additional soft debt or deferred developer fee. In the worked example, pricing the same $10.2M of credits at $0.90 instead of $0.85 would change equity by $510,000. Use current pricing from your syndicator.
• Confusing the bond test with bond sizing. Total bond financing has to meet the applicable test (50% of the aggregate basis of building and land, or 25% where the post-2025 alternative applies); falling short loses the 4% credits that come without a competitive allocation. Permanent debt is a separate question: size it to DSCR, and redeem any bonds above that amount at conversion. Carrying more permanent bonds than NOI supports means unnecessary debt service.
• Not stress-testing the stack. What happens if one soft source falls out? What if credit pricing drops 4 cents? What if interest rates rise 50 basis points? The capital stack should be tested under adverse scenarios, not just modeled at par.

How to Model It

The capital stack model is the centerpiece of a LIHTC pro forma. Here's how to structure it:

Sources and uses matrix

A single worksheet that shows all uses (left column) and all sources (top row), with each cell showing how much of each use is funded by each source. The column totals equal each source's commitment amount. The row totals equal each use's total cost. The grand total in the bottom-right corner equals TDC. This matrix format makes it immediately clear which sources fund which uses, and where gaps exist.

Debt service waterfall

A 15-year (minimum) annual projection showing: gross revenue → vacancy → effective gross income → operating expenses → NOI → senior debt service → replacement reserves → asset management fee → surplus cash flow → deferred developer fee repayment → soft debt repayment (if residual receipts). Each soft lender has a position in this waterfall. The order matters and is specified in the intercreditor agreements.

Sensitivity toggles

At minimum, the model should toggle three variables independently: credit pricing (±$0.05), interest rate on hard debt (±100 bps), and soft debt amount (±$1M). For each toggle, the model should show the impact on: total sources, gap/surplus, annual debt service, DSCR, and deferred developer fee repayment period. If changing one variable breaks the deal, you know where the risk is concentrated.

Related Articles

This article is part of the LIHTC underwriting series. Each article goes deeper into a specific aspect of tax credit deal structuring:

• LIHTC 101: How the Program Works. The foundational overview of 4% vs 9% credits, credit calculations, and deal structure.
• Rent and Income Limits. AMI calculations, maximum rents by household size, and set-aside elections.
• Acquisition/Rehab with 4% Bonds. Modeling existing property deals with rehabilitation credits.
• 4% LIHTC with Tax-Exempt Bonds. Bond deal mechanics, the 25% test, and how to size the bond tranche.
• LIHTC Investor Returns. Credit pricing mechanics, investor yield calculations, and pay-in schedule structuring.
• Year 15 Exit Strategies. Compliance period obligations, resyndication, and disposition options.