One-to-four unit rentals: the fourplex and the five-plex live in different legal universes

A fourplex and a five-plex are the same business, one apartment apart, and they are financed in different legal universes. Below five units the property is residential real estate, and its debt lives in the world of consumer mortgage rules, personal recourse, agency conforming limits, and a cap on how many financed properties one borrower can hold. At five units it becomes commercial multifamily, and the cheapest nonrecourse long-term money in the country opens up. Investors who build a portfolio of small rentals spend years inside the first world without knowing the second exists, and the unit count is the only thing keeping them there.

One-to-four unit property is residential lending: consumer-style rules, personal recourse, and a cap on how many you can finance. The fifth unit moves the same building into commercial multifamily and a different set of lenders entirely.

The three ways to finance a small rental

An investor buying a one-to-four unit rental has three lending worlds. Conventional conforming loans, the Fannie and Freddie residential products, offer the lowest rates and thirty-year fixed terms, underwritten on the borrower’s personal income and credit, with recourse, a limit on the number of financed properties a borrower can carry, and a down payment that rises for investment property. Portfolio and bank loans, from a community bank or credit union that keeps the loan, underwrite the borrower and the relationship and will go past the conforming property count, usually at a higher rate with a shorter fixed period and a balloon. And DSCR loans, the non-QM product that underwrites the property’s rent instead of the borrower’s income, lets an LLC take title, and scales past every conventional limit, at a higher cost and usually with a prepayment penalty.

Each world has a different answer to the question that matters most to a growing investor: how many of these can I own. Conventional caps it. Portfolio lenders stretch it. DSCR removes it, at a price.

Why these loans are different from everything else in the pillar

Residential investment lending sits inside a legal framework the rest of this pillar barely touches. A loan to an individual on a one-to-four family home triggers the residential regimes: the federal consumer-mortgage rules where the borrower occupies, the state mortgage-licensing laws that govern who may originate and broker these loans, and the agency conforming guidelines. The DSCR product works precisely by stepping outside part of that framework, treating the non-owner-occupied rental loan as business-purpose credit, and the line it stands on, owner occupancy, is the line this whole class turns on. An investor who occupies one unit of a duplex is on the consumer side; the same investor renting all units is on the business side; and the lender, the licensing, and the enforceable terms change with that fact alone.

The guaranty, the LLC, and the due-on-sale trap

Two seams this pillar has already taught arrive together in small residential. Nearly all of these loans are recourse, and conventional loans require the borrower to be a natural person, so the investor who wants the LLC’s liability shield around a rental cannot simply borrow conventionally in the LLC’s name. The common workaround, buy and finance personally, then deed the property into an LLC, is exactly the transfer that triggers the due-on-sale clause, because federal law exempts transfers to trusts and family but not to LLCs. The investor is choosing between the cheap conventional loan with the property in their own name, the DSCR or portfolio loan that permits LLC title at a higher rate, or a transfer that hands the lender a right to call the loan. That choice is the central structuring decision of small-rental investing, and the lender type decides it.

The fifth unit

Everything changes at five units, and the change is worth planning around. A five-plus-unit building is commercial multifamily: eligible for Fannie Mae and Freddie Mac multifamily programs, for HUD, and for the whole institutional tier, on nonrecourse terms with the standard carve-outs, thirty-year amortization, no financed-property cap, and the entity as borrower by default. The same investor who was stacking DSCR loans on fourplexes can refinance a single five-unit building into agency debt with no personal recourse. The five-unit line is a legal cliff, and an investor comparing a fourplex to a small apartment building is comparing two financing regimes, not two properties. The multifamily playbook covers what changes in the operating rules at the same threshold.

What to decide before you buy

Decide which lending world you are building in, because the choice compounds across a portfolio. If you want conventional rates, accept personal title and the property cap, and do not deed into an LLC afterward without the lender’s written consent. If you want LLC title and scale, price the DSCR or portfolio loan in full, including its prepayment penalty and its vesting rules. And if you are approaching the conforming cap or the limits of recourse, look hard at whether the next acquisition should be the fifth unit rather than the fourth fourplex, because the building on the other side of that line is financed by lenders who do not want your tax returns, do not want your personal guaranty, and will lend for thirty years.