Capital Stack
The full set of loans, equity, and subsidies that pays for a housing development, ranked by who gets repaid first and who takes the most risk.
What Is a Capital Stack?
A capital stack is the combination of every funding source used to pay for a real estate development: loans, investor equity, grants, and the developer’s own money. Practitioners picture it as a vertical stack. The safest money sits at the bottom and is repaid first. The riskiest money sits at the top and is repaid last, if at all.
Every development has a capital stack. In affordable housing it tends to be taller and more complicated, because rents are kept low on purpose.
How the Capital Stack Works
A typical affordable rental stack has three broad layers:
| Layer | Common sources | Repayment priority |
|---|---|---|
| Senior debt | Bank, state agency, or FHA-insured first mortgage | Paid first from rental income; first claim on the property if the borrower defaults |
| Subordinate or soft debt | State and local housing loans, federal HOME or CDBG funds | Paid after senior debt, often only from leftover cash flow, or deferred |
| Equity | Tax credit investors, the developer’s cash, a deferred developer fee | Paid last; carries the most risk |
The size of the senior loan is limited by how much net operating income the property produces. Lenders test this with a debt service coverage ratio. In a market-rate deal, a 2025 Shelterforce primer notes, the senior loan typically covers 60% to 80% of the project’s financing. Restricted rents produce less income, so an affordable project can usually borrow less. The shortfall is the funding gap, which is closed with tax credit equity under the Low-Income Housing Tax Credit, soft debt, and grants.
Example
Suppose a 60-unit apartment building costs $20 million to build. Its restricted rents support a $6 million first mortgage. Tax credit investors contribute $10 million in equity. A state housing trust fund lends $2.5 million and a county lends $1 million, both repayable only from surplus cash flow. The developer defers $500,000 of its fee. Together those five sources equal the $20 million cost.
Why It Matters for Workforce Housing
Each extra layer brings its own application, deadlines, and compliance rules. In 2026 research by the Federal Reserve Bank of Kansas City, developers described navigating 12 sources of financing for a single project, with requirements that often conflicted and separate application timelines. The resulting delays raise holding costs.
Homes for households earning roughly 80% to 120% of area median income are usually above tax credit limits. Their stacks lean instead on local loans, employer contributions, donated land, or investors willing to accept lower returns. For more, see how workforce housing is financed.
Sources
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