Commercial vs Residential Financing
Commercial vs Residential Financing
The five-unit threshold divides the lending world. Below it, you borrow on residential terms (Fannie Mae, ARM caps, QM rules). At five units and above, you enter commercial lending—where balloon loans, floating rates, and personal guarantees are standard.
Key takeaways
- Fannie Mae and Freddie Mac cap residential loans at four-unit properties; five units and above fall under commercial lending rules
- Residential mortgages (≤4 units) can be 30-year fixed; commercial mortgages (5+ units) typically balloon after 5, 7, or 10 years
- Commercial loans charge 50–150 basis points more than residential loans on similar LTV; rates float more often
- Personal guarantees are standard on commercial loans under $2M; residential mortgages for investment property rarely require them
- Commercial lenders underwrite on net operating income and debt service coverage ratio; residential lenders underwrite on your credit and income
The Five-Unit Dividing Line
The defining threshold in commercial vs. residential financing is the number of units. One through four units are residential mortgages; five units and above are commercial mortgages. This line exists because Fannie Mae and Freddie Mac (the government-sponsored mortgage aggregators) can only purchase loans on 1–4 unit properties. Once you cross into five units, you've left the Fannie Mae conforming loan market and entered the commercial mortgage market, where loan terms, products, and pricing follow entirely different rules.
A duplex, triplex, or fourplex qualifies for residential mortgage programs (30-year fixed, lower rates, no personal guarantee). A five-unit apartment building does not. The property type doesn't change—it's still residential (families living in it)—but the underwriting framework does. This creates a sharp incentive for investors: a fourplex can be held with a 30-year fixed mortgage at 6.5% (2026 rates), locked in for life. A five-unit building must refinance the entire loan balance every 5–7 years, at whatever rates prevail then.
The impact on cap rates is measurable. A fourplex in the same neighborhood as a five-unit apartment might sell at 4.5% cap rate; the five-unit might trade at 5.5% cap rate—a 100 basis point spread driven entirely by the financing difference. Buyers of five-plus unit properties must account for refinance risk in their projections.
Residential Mortgages (≤4 Units)
Residential mortgages on investment properties follow Fannie Mae guidelines. You can get:
- 30-year fixed at 6.5–7.0% (2026 market)
- 15-year fixed at 6.0–6.5%
- 5/1, 7/1 ARMs at 5.8–6.5%, resetting to prime + 2.5% after initial period
- 25% down minimum; some lenders require 30% for investment (owner-occupied is 10–20%)
- 50 basis points added for investment property (vs. owner-occupied)
- Debt service coverage ratio requirement: 1.2–1.5x (varies by lender)
Fannie Mae limits investors to 10 properties financed under their guidelines (the "10-property cap"). Once you own 10, you must use portfolio lenders or commercial lenders for the 11th property. This cap forces sophisticated investors to portfolio-ladder: own 10 residential mortgages, refinance one into a portfolio loan when buying the 11th, repeat.
Commercial Mortgages (5+ Units)
Commercial mortgages are the standard for apartment buildings, office, retail, and industrial. Key features:
- Balloon loans: Principal is not fully amortized. A 7/1 balloon amortizes over 30 years but balloons (full remaining balance due) after 7 years. You must refinance or sell on year 7. A 5/1 balloon at 6.8% might cost $680k/year in debt service on a $2M loan, but the remaining $1.6M is due in a lump sum.
- Floating rate loans: Interest-only loans at prime + 2.5–4.0%. Common on stabilized assets during the hold period.
- Prepayment penalties: Yield maintenance or step-down (3–5% in year 1, declining to 0% by year 5). Prevents refinancing in a down-rate environment.
- Personal guarantees: Standard for loans under $2M. You sign a full recourse guarantee; the lender can pursue you personally if the property defaults. Larger loans may negotiate non-recourse or recourse-lite terms.
- DSCR minimum: Usually 1.25x for stabilized properties; 1.0x for value-add (see "The DSCR Spectrum by Lender").
Rates on commercial loans are 50–150 basis points higher than residential on the same LTV. A $2M commercial loan on a $4M five-unit building (50% LTV) might be 6.8–7.2% (5/1 balloon); a $2M residential loan on a $4M fourplex (same 50% LTV) would be 6.5%.
Loan-to-Value and Leverage Differences
Residential mortgages cap leverage at 80–85% LTV for investment property. Commercial mortgages allow up to 75–80% LTV on stabilized assets, though value-add properties might go 65–75% LTV to account for execution risk.
A fourplex bought for $500k with 25% down ($125k) and a $375k mortgage (75% LTV) is fully residential. The same fourplex with 20% down and an $400k mortgage (80% LTV) would require a portfolio lender if you wanted to exceed 75%, or you'd have to bring another 5% cash.
A five-unit building bought for $1M requires commercial financing. At 70% LTV, you need $700k in debt; at 75% LTV, you need $750k. The lender has significant discretion. If the property is stabilized with 1.5x DSCR, 75% LTV is standard. If it's a value-add (partially vacant, rent growth potential), 65% LTV might be the ceiling.
Amortization and Balloon Risk
The 5/1 or 7/1 balloon is the single biggest operational constraint in commercial real estate. It forces a refinancing event every 5–7 years, regardless of how well the property is performing.
If you buy a five-unit building in 2026 with a 7/1 balloon at 6.8%, the loan is due in 2033. Your projection must assume you can refinance at prevailing 2033 rates. If rates rise to 8% by then, your debt service jumps. If the property appreciates, you might refinance into a larger loan and pull cash. If the property underperforms, you might not qualify for refinancing and will be forced to sell.
Investors often assume rates will be lower at refinance (the "rate assumption risk"). This is dangerous. Smart operators model:
- Base case: Rates unchanged. 7/1 balloon refinances at 6.8% again.
- Bear case: Rates up 150 bps. 7/1 balloon refinances at 8.3%.
- Bull case: Rates down 100 bps. 7/1 balloon refinances at 5.8%, pull cash on apprec.
Only pursue the deal if the bear case still generates acceptable returns (positive cash flow, acceptable cap rate).
Personal Guarantees in Commercial Lending
A personal guarantee on a commercial loan means you are liable for the full loan balance if the property defaults. Your other assets—bank accounts, other real estate, business interests—can be pursued by the lender.
On a $1M commercial loan, a personal guarantee is standard for most lenders. The only escape is:
- Loan size over $2M (some non-recourse lenders exist)
- Sponsor strength (large operators with significant net worth might negotiate non-recourse; Blackstone and private equity firms routinely get non-recourse terms)
- Specific loan program (some conduit lenders offer limited recourse, capped at 1–2% of original loan balance)
This is a material difference from residential mortgages, where the lender's recourse is limited to the property (the house cannot owe more than its value; the deficiency is often forgiven on owner-occupied, though not on investment property in many states).
Underwriting: Income vs. Income
Residential underwriting focuses on your income—your job, salary, savings, credit score. The lender is comfortable because you're a stable wage earner. The property's rental income is secondary (used to satisfy the DSCR, but not the primary qualification path).
Commercial underwriting focuses on the property's income—the NOI (net operating income). The lender doesn't care if you're a doctor or a plumber. They care if the building generates enough cash to service the debt and provide a cushion (DSCR). Your credit and reserves matter, but the property's cash flow is primary.
This flip is profound. A six-figure salary helps a little on a commercial loan, but it won't carry a deal with poor unit economics. Conversely, a property with strong NOI can be financed even if you have a modest job, as long as your credit is good.
Flowchart: Residential vs Commercial Decision
Transition from Residential to Commercial
Many investors start with a fourplex (residential financing, simple 30-year fixed) and graduate to a five-unit building. The transition is abrupt. The fourplex lender will not finance the five-unit; you must switch lenders entirely. The five-unit balloon matures in 5–7 years, forcing a refinance or sale.
Smart investors manage this transition by:
- Purchasing the fourplex first (residential, fixed rate, low risk)
- Building the operation and cash reserves
- Graduating to a five-unit with strong cash flow and a portfolio lender (easier underwriting than banks)
- Stacking portfolio loans on multiple five-unit buildings
- Eventually, if large enough, accessing institutional capital (conduit, life company, CMBS)
Related concepts
Next
The five-unit line reshapes everything: rates, amortization, guarantees, underwriting. But within commercial lending itself, loan terms vary wildly based on property type, condition, and lender appetite. The next article examines interest-only loans—a middle ground between aggressive leverage and conservative fixed payment—and when they make sense for cash-flow optimization versus buy-and-hold stability.