LIHTC Acquisition/Rehab with 4% Bonds: Dual Basis, Eligible Costs, and the Resyndication Pipeline

Key Takeaways

Why Acquisition/Rehab

An acquisition/rehab deal buys an existing building and renovates it with new tax credits. Older LIHTC properties reaching Year 15 are a recurring source of these deals: they are acquired by a new (or existing) developer, rehabilitated, and re-entered into the LIHTC program for a new 15-year compliance period. HUD's 2012 study "What Happens to Low-Income Housing Tax Credit Properties at Year 15 and Beyond?" (prepared by Abt Associates) reported that, as of 2010–2011, a brokerage firm estimated 15–20% of LIHTC sales were being resyndicated, and syndicators estimated a similar 15–20% of Year 15 properties. From about 2005 to early 2008, as much as 80% of the firm's brokered sales went to buyers who intended to resyndicate. This creates a recurring pipeline of deals that works differently from new construction.

An existing affordable property has operating history, established tenancy, and known physical condition, and the acquisition price is often below replacement cost. The trade-off: the developer must navigate a more complex credit calculation (dual basis), comply with additional IRS rules (the 10-year rule, related-party restrictions), and manage construction within an occupied building.

This article focuses on the 4% path, where the deal is financed with tax-exempt private activity bonds. The 4% credits are noncompetitive: they depend on the availability of bonds within the state's private activity bond ceiling rather than on winning a competitive 9% allocation. HUD's Year 15 study notes that 4% credits may be more readily accessed than 9% credits for preservation projects, although bond financing brings its own transaction costs and complications.

The Dual Basis Structure

The defining feature of a LIHTC acquisition/rehab deal is the dual basis calculation. The IRS treats the acquisition component and the rehabilitation component as separate credit-generating events, each with its own eligible basis and its own credit rate.

Acquisition basis

The acquisition eligible basis is the purchase price of the existing building (excluding land), as defined in IRC Section 42(d)(2). Land is never included in basis. The acquisition basis earns the "30% present value credit" for existing buildings under IRC Section 42(b)(1)(B)(ii), with a 4% floor under Section 42(b)(3) for buildings placed in service after 2020. That holds whether the project uses bonds or receives a competitive 9% allocation.

Key constraint: the acquisition basis does not qualify for the 130% basis boost in Qualified Census Tracts or Difficult Development Areas. Under IRC Section 42(d)(5)(B), the boost applies only to new construction basis and, for an existing building, to the rehabilitation expenditures.

Rehabilitation basis

The rehabilitation eligible basis is the total of all qualified rehabilitation expenditures: the hard and soft costs of the renovation work that are chargeable to capital account. The statute treats these expenditures as a separate new building (IRC Section 42(e)(1)). If the project uses tax-exempt bonds (4% deal), the rehab basis generates the 4% credit. In a competitive 9% acquisition/rehab deal, the acquisition basis earns the 4% credit and the rehab basis (if not bond-financed) earns the 9% credit, both under the same competitive award. That is the standard 9% acquisition/rehab structure.

The rehabilitation basis does qualify for the 130% basis boost if the project is in a QCT or DDA. This is an important asymmetry: the boost applies to rehab but not to acquisition. In a deal where the rehab budget is a large share of total cost, the boost can significantly increase total credits.

Combined credit generation

The total annual credit is the sum of the acquisition credit and the rehabilitation credit, calculated independently:

Acquisition credit: Acquisition basis × applicable fraction × 4% rate
Rehabilitation credit: Rehab basis × applicable fraction × 4% (or 9%) rate
Total annual credit: Acquisition credit + Rehabilitation credit

The 10-Year Rule

To claim the 4% acquisition credit, the building must meet the 10-year rule in IRC Section 42(d)(2)(B)(ii): there must be a period of at least 10 years between the date the taxpayer acquires the building and the date the building was last placed in service. Certain placements in service are disregarded under Section 42(d)(2)(D)(i), including carryover-basis transfers, inheritances, and some foreclosure resales. The former "nonqualified substantial improvement" test was repealed in 2008.

Exceptions to the 10-year rule

The statute provides several exceptions that are critical for practitioners:

• Federally or state-assisted buildings. Buildings substantially assisted, financed, or operated under HUD Section 8, National Housing Act Section 221(d)(3), 221(d)(4) or 236, USDA Section 515, any other HUD or Rural Housing Service housing program, or a similar state program are exempt from the 10-year rule (IRC Section 42(d)(6)). This is a major exception because many acquisition/rehab targets are older assisted properties.
• Foreclosure resales (limited). A placement in service by a purchase-money lender that took the building by foreclosure or deed in lieu is disregarded if the lender resells within 12 months and its own placement in service met the 10-year test (IRC Section 42(d)(2)(D)(i)(IV)).
• Failed depository institutions. On application, the IRS may waive the rule for a building acquired from an insured depository institution in default, or from its receiver or conservator (IRC Section 42(d)(6)(B)).

Year 15 LIHTC properties normally satisfy the 10-year rule on their own, because the building was last placed in service well over 10 years before the new acquisition. A buyer who acquires before the end of the prior owner's compliance period does not get new acquisition credits; under IRC Section 42(d)(7), it steps into the prior owner's remaining credits.

The related-party rule

Under IRC Section 42(d)(2)(B)(iii), the acquisition credit is unavailable if the building was previously placed in service by the taxpayer or by a person related to the taxpayer at that time. Related status is defined in Section 42(d)(2)(D)(ii) by reference to IRC Sections 267(b) and 707(b)(1), generally more-than-50% common ownership, plus common control under Section 52. In addition, the "purchase" requirement in Section 42(d)(2)(B)(i), which borrows the definition in Section 179(d)(2), excludes acquisitions from related sellers under the Section 267 and 707(b) tests, with family limited to a spouse, ancestors, and lineal descendants. The 10% threshold that applied before the Housing and Economic Recovery Act of 2008 no longer applies. These rules prevent developers from selling properties to themselves (or affiliated entities) to generate new credits.

In Year 15 resyndications, this rule requires careful structuring. If the existing general partner wants to remain involved in the resyndicated deal, the buyer has to clear two tests: the Section 179(d)(2) purchase test at the acquisition date (the more-than-50% thresholds in Sections 267(b) and 707(b)(1), plus the controlled-group rule), and the Section 42(d)(2)(B)(iii) test, which asks whether the buyer was related, including under Section 52 common control, to the party that placed the building in service when it did so.

Eligible Rehab Expenditures

Not every dollar spent on rehabilitation qualifies for the LIHTC. The eligible basis includes only expenditures that are properly chargeable to capital account and incurred in connection with the rehabilitation (IRC Section 42(e)(2)(A)): costs that extend the useful life of the building or adapt it to a new use. This distinction matters because ineligible costs reduce the credit amount and can create an unresolved gap in the capital stack.

Eligible costs

• Structural repairs and replacements: Roof replacement, foundation repair, structural framing, exterior walls and cladding
• Building systems: HVAC replacement, plumbing, electrical (including panel upgrades), elevator modernization, fire suppression
• Unit interiors: Kitchen and bath renovation, flooring, fixtures, appliances (if installed as part of the rehab scope), cabinets, countertops
• Accessibility improvements: ADA compliance work, accessible unit conversions, common area accessibility
• Energy efficiency upgrades: Insulation, window replacement, high-efficiency mechanical systems, solar (if building-integrated)
• Soft costs attributable to rehab: Architecture and engineering for the rehab scope, construction management, environmental remediation (lead, asbestos), construction period interest, permits
• Site improvements: Parking lot resurfacing, site drainage, landscaping (if part of the overall rehab scope; treatment varies by state)

Ineligible costs

• Land and land improvements not integrated with the building
• Personal property not permanently attached to the building (furniture, movable equipment)
• Acquisition cost of the building (this goes into acquisition basis, not rehab basis)
• Operating expenses disguised as capital (routine maintenance, minor repairs that don't extend useful life)
• Costs attributable to commercial space in mixed-use buildings
• Syndication and organizational costs

Substantial Rehabilitation Threshold

To qualify for rehabilitation credits, the project must meet the substantial rehabilitation test under IRC Section 42(e)(3): rehabilitation expenditures during any 24-month period must equal or exceed whichever of the following requires the greater amount:

• $8,700 of qualified basis per low-income unit for expenditures placed in service in 2026 (the statutory $6,000 floor, indexed annually; Rev. Proc. 2025-32), or
• 20% of the adjusted basis of the building as of the first day of the 24-month expenditure period

For an existing building, the test also controls the acquisition credit. Under IRC Section 42(d)(2)(B)(iv), the acquisition basis is zero unless a rehabilitation credit is allowable for the building (outside the narrow exception in Section 42(f)(5)(B)).

In the illustrative example in Figure 1, the 20% test is the binding one. Assuming the building's adjusted basis equals the $9.6M acquisition basis when the 24-month period starts, 20% is $1,920,000 ($16,000 per unit), against $1,044,000 under the $8,700 test ($8,700 × 120 units). The $12.8M rehab basis clears both. The 20% test matters most for properties acquired at high prices, where the adjusted basis is substantial.

State HFAs often set rehabilitation minimums above the federal floor in their QAPs. HUD's Year 15 study found that state HFAs often have rehabilitation requirements that exceed the federal statute, and that syndicators interviewed for the study cited minimum rehabilitation requirements of $25,000–$40,000 per unit for new syndications. Some owners of resyndicated properties pointed to construction budgets of $68,000, $80,000, and even $130,000 per unit.

The 24-month expenditure period

The developer selects the 24-month period. All rehabilitation expenditures within that window count toward the substantial rehabilitation test. The rehabilitation expenditures are treated as placed in service at the close of the 24-month period over which the minimum is measured (IRC Section 42(e)(4)(A)), and the acquisition credit period cannot begin before the rehab credit period (Section 42(f)(5)(A)). This date is critical: it drives the start of the 10-year credit period and the 15-year compliance period.

For occupied buildings, the 24-month period must account for phased construction. Tenants cannot all be relocated at once, so the rehab proceeds unit by unit or building by building. The developer must plan the construction schedule to ensure all expenditures fall within the elected 24-month window while minimizing tenant disruption.

The Year 15 Resyndication Pipeline

Year 15 is the end of the initial LIHTC compliance period. At this point, the investor's credits have been fully delivered, the extended use agreement remains in effect, and the property typically needs capital reinvestment after 15 years of operation under restricted cash flow. This creates a natural acquisition/rehab opportunity.

How resyndication works

1. Investor exit. The limited partner (investor) exits the partnership, typically by selling their interest to the general partner for a nominal amount or through a put/call option specified in the partnership agreement. The investor's economic interest in the property was the tax credits, which have been fully claimed.
2. Property transfer. The general partner (or a new developer) acquires the property. If the GP acquires it, the related-party rules apply and must be navigated. If a new developer acquires it, the transaction is more straightforward.
3. Physical needs assessment. A new PNA establishes the rehab scope. After 15 years, a property often needs significant capital work: roof replacement, HVAC overhaul, unit interiors, accessibility upgrades, and energy efficiency improvements.
4. New credit application. The developer applies for new 4% credits (paired with bonds) or 9% credits (competitive allocation). The acquisition basis is the purchase price of the building (minus land). The rehab basis is the cost of the renovation work.
5. New compliance period. The resyndicated property enters a new 15-year compliance period with a new investor, new financing, and renewed physical condition.

Acquisition pricing in resyndications

The acquisition price in a Year 15 resyndication is a negotiated value, but it is constrained by two factors: the property's appraised value (required by the syndicator and senior lender) and the project's ability to carry the resulting debt or generate sufficient acquisition credits. In many resyndications, the acquisition price is well below replacement cost because the property's income is restricted and its physical condition has deteriorated.

A lower acquisition price shrinks the acquisition credit component, and the rehab basis also earns the 130% boost in a QCT or DDA. In the illustrative example in Figure 1, the rehab component produces $665,600 of the $1,049,600 annual credit (63%), even though the $12M purchase price is close to the $14M rehab budget. This is the inverse of a market-rate acquisition where the purchase price dominates: in a LIHTC resyndication, much of the value is created by the rehab investment, not the acquisition.

Common Mistakes

These errors can derail acquisition/rehab underwriting:

• Applying the basis boost to acquisition basis. The 130% QCT/DDA boost applies to rehabilitation basis only. Applying it to acquisition basis overstates credits by 30% on the acquisition component. In the illustrative example in Figure 1, that is $115,200 a year ($9.6M × 30% × 4%), or $1,152,000 over 10 years.
• Ignoring the 10-year rule. If the building was last placed in service within the past 10 years (and no exception applies), there is no acquisition credit. The entire deal economics change if the acquisition credit is eliminated. Verify the placed-in-service history before underwriting.
• Conflating acquisition price with acquisition basis. Acquisition basis is the purchase price minus the land allocation and any ineligible items. If the purchase price includes land, furniture, or other non-basis items, those must be carved out. An appraisal with a land/building split is essential.
• Underestimating the rehab scope. The PNA must be comprehensive. Missing a major building system (roof, HVAC, plumbing) means the rehab budget is understated, which means credits are understated and the deal has an unresolved gap. Worse, discovering the deficiency during construction creates a change order that may not qualify for basis if it falls outside the 24-month expenditure period.
• Missing the substantial rehabilitation threshold. The developer must verify that rehab expenditures equal or exceed the greater of $8,700 of qualified basis per low-income unit (2026) or 20% of adjusted basis within the elected 24-month period. If the rehab scope is modest and the adjusted basis is high (because of a high acquisition price), the 20% test may not be met. Failing the test eliminates not only the rehab credit but, under IRC Section 42(d)(2)(B)(iv), the acquisition credit as well.
• Failing to allocate costs between acquisition and rehab basis. Soft costs must be allocated to the correct basis pool. Architecture fees for the rehab go in rehab basis. Legal costs for the acquisition go in acquisition basis (or are excluded from basis entirely, depending on the nature of the cost). Misallocation shifts credits between the two pools and can trigger errors on the 8609.
• Not planning for tenant relocation. Occupied rehab requires a relocation plan, temporary housing for displaced tenants, and compliance with the Uniform Relocation Act if federal funds are involved. Relocation costs are real and must be budgeted; the illustrative example in Figure 3 carries $480,000, or $4,000 per household across 120 units. Some of these costs may not be includable in eligible basis, and Figure 3 treats them as excluded.

How to Model It

An acquisition/rehab pro forma requires several tabs that don't exist in a standard new construction LIHTC model:

Acquisition basis tab

Purchase price → land allocation (from appraisal) → building value → less ineligible items → eligible acquisition basis → applicable fraction → qualified acquisition basis → × 4% rate → annual acquisition credit. No basis boost. This calculation uses the existing-building (30% present value) rate with its 4% floor, regardless of whether the rehab is bond-financed or receives a 9% allocation.

Rehabilitation basis tab

Hard rehab costs (from PNA/scope of work) + eligible soft costs → total rehab expenditures → less ineligible items → eligible rehab basis → basis boost (if QCT/DDA) → applicable fraction → qualified rehab basis → × 4% (or 9%) rate → annual rehab credit. Include the substantial rehabilitation test: within 24 months, do the expenditures meet both $8,700 of qualified basis per low-income unit (2026) and 20% of adjusted basis? If not, both the rehab and acquisition credits drop out.

Combined credit and equity tab

Acquisition credit + rehabilitation credit = total annual credit × 10 years × credit pricing = total tax credit equity. This tab should show the contribution of each basis pool to the total equity, so the underwriter can see which component is driving the deal economics.

Physical needs assessment integration

The PNA should be summarized in a tab that maps building systems to cost estimates, useful life, and replacement timing. This tab drives the rehab budget and ensures alignment between the PNA, the scope of work, the construction contract, and the eligible basis calculation. If the construction contract exceeds the PNA-supported scope, the excess may need to be justified to the HFA and syndicator.

Sensitivity analysis

For acquisition/rehab deals specifically, test: acquisition price (±10%), rehab scope (±15%), credit pricing (±$0.04), and interest rate (±75 bps). Show the impact on total credits, equity, gap, and DSCR. The rehab scope sensitivity is particularly important because construction cost escalation during predevelopment can materially change the deal economics.

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.
• The LIHTC Capital Stack: Soft debt, deferred developer fee, HOME funds, and gap financing.
• 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.