Federal government insures second mortgages for backyard housing units
H.R. 4479 — To amend the National Housing Act to direct the Secretary of Housing and Urban Development to establish a program to insure certain second liens secured against property for the purpose of financing the construction of an accessory dwelling unit, and for other purposes. · Filed by Sam Liccardo (D-CA) · 16 cosponsors · Introduced Jul 17, 2025 · Referred to committee
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What it does
This bill creates a federal mortgage insurance program for second mortgages used to finance accessory dwelling units (ADUs)—small residential units added to single-family homes. Homeowners can borrow up to 30% of a standard home loan limit (or more if rental income is projected), and the federal government insures the lender against default. Fannie Mae and Freddie Mac are permitted to buy and resell these insured loans, expanding the secondary market.
Why we flagged it
The bill's core mechanism is a federal insurance program designed to reduce financing barriers for ADU construction. This is a supply-side housing policy, not a subsidy or deregulation, and directly addresses housing affordability through increased inventory.
What the text implies
- Fannie Mae and Freddie Mac securitization of ADU loans may concentrate housing finance risk in government-sponsored enterprises, potentially exposing taxpayers to losses if ADU rental markets underperform.
- The 50% rental-income boost to loan limits incentivizes ADU construction primarily for investment/rental purposes, which may price out owner-occupants seeking personal housing solutions.
- No explicit affordability requirements or rent controls are mentioned; ADU units financed under this program may command market-rate rents, limiting benefit to low-income renters.
- State and local zoning restrictions on ADUs are not addressed; the federal financing program may be underutilized in jurisdictions that prohibit or severely limit ADU construction.
Section numbers refer to the bill text the analysis read — linked under Primary records below.
Who it affects
The program lowers barriers for homeowners to build ADUs, which increases housing supply and creates affordable rental options. Homeowners gain access to federally insured credit at lower cost, and renters benefit from additional housing stock. The insurance premium (max 1% annually) is modest and transparent.
Who stands to gain
- mortgage lenders and banks (reduced default risk via federal insurance)
- Fannie Mae and Freddie Mac (expanded loan purchase and securitization opportunities)
- homeowners with equity and creditworthiness to access second mortgages
- construction and prefabrication companies (increased ADU demand)
Named in the bill
Department of Housing and Urban Development (HUD), Federal Housing Finance Agency (FHFA), Federal National Mortgage Association (Fannie Mae), Federal Home Loan Mortgage Corporation (Freddie Mac), National Housing Act, Housing and Community Development Act of 1974
Where it stands
16 cosponsors: 16 Democrats.
- Jul 17, 2025 — Introduced · Congress.gov: “Introduced in House”
- Jul 17, 2025 — Referred to House Committee on Financial Services · Congress.gov: “Referred to the House Committee on Financial Services”
Dates and quoted wording are Congress.gov's action record; the timeline shows status changes, not every procedural step.
Money around this bill
1 lobbying clients named this bill on 2 disclosure filings across 2 quarters, Dec 2025 to Jun 2026. Those filings disclosed $100,000 in lobbying spend. A filing names 2 bills on average, so that figure is what each filing reported, not a share belonging to this bill.
More lobbying clients named this bill than 0% of bills with at least one filing.
Sam Liccardo, the sponsor, reported $724,267 in PAC receipts in the 2026 cycle.
- Lantheus Medical Imaging, Inc. — $100,000 on 2 filings
Lobbying Disclosure Act filings through Jul 20, 2026. A filing shows who paid to lobby on a bill it names, not what changed.
How this was measured
Analysis — Quorum's AI read the bill text published by Congress.gov (4,177 characters) on Jun 3, 2026. Section numbers in the findings refer to that text, linked below; transparency and hidden-provision scores are compared against the median of 16,222 analysed bills.
Status and sponsors — Congress.gov's bill record — actions, committee referrals and cosponsors — loaded nightly. The timeline shows status changes, not every procedural action.
Money — Senate Lobbying Disclosure Act filings whose specific-issue field names this bill for quarters ending Dec 2025 to Jun 2026. A filing's amount is reported whole beside the median number of bills a filing names; it is never divided across them. PAC receipts are FEC-reported contributions to the sponsor's candidate committee in the 2026 cycle.
As of — lobbying records through Jul 20, 2026 · page rendered 2026-10-20.
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