Multifamily Supplemental Loans from Fannie Mae and Freddie Mac Multifamily Supplemental Loans from Fannie Mae and Freddie Mac

By Multi-Family USA Editorial Team · Reviewed by Josh Bauerle · Published 2026-10-08 · Updated 2026-10-08 · 12 min read

What is a multifamily supplemental loan?

A supplemental loan is a second mortgage that sits behind an existing agency first mortgage on the same apartment building. Instead of refinancing the whole balance, you borrow additional money against the equity you have built through appreciation, higher rents or principal paydown, and the first loan stays exactly as it is. The supplemental is a separate note, secured by a subordinate lien, and it can be used for renovations, buying another property, returning capital to partners or building reserves.

It is a narrow product. Both Fannie Mae and Freddie Mac offer supplementals only behind their own first loans, and only through the lender that is already involved in the first loan. If your first mortgage is a bank, CMBS or HUD loan, this page does not apply. See bank loans, CMBS loans and HUD 223(f) for those structures. For the first loans that supplementals attach to, start with agency stabilized loans, Fannie Mae small loans and Freddie Mac Optigo.

Terms below come from Fannie Mae’s Multifamily Guide, the Fannie Mae supplemental term sheet as republished by DUS lender Lument, and Freddie Mac’s Optigo Supplemental Loan product sheet (dated 11/25) and fixed-rate product sheet (dated 4/26). Both agencies say terms can change and lenders can add overlays, so use every figure as a starting point for a written quote.

Supplemental loan terms at a glance

Freddie Mac’s base maximum LTV and minimum DCR depend on the remaining term and payment type:

Freddie Mac adds that the maximum combined maturity LTV is 70%, subject to adjustment for certain property and loan types, and that partial-term interest-only requires at least 2 years of amortization.

Two things are not on either term sheet: a closing timeline and a rate. Ask the servicer for both, and see the rates page for market context only.

How supplemental loans are sized

The combined test

The key difference between a supplemental and a stand-alone loan is that the tests run on the whole stack. Fannie Mae’s Guide, in Part III, Chapter 13 (Section 1302.03C in the current version, numbered 1402 in older ones), tells the lender to apply the Form 4660 DSCR and LTV requirements to the combined debt service of all pre-existing loans plus the supplemental, and to the combined unpaid balance of the pre-existing loans plus the supplemental principal. Freddie Mac’s sheet says the same: all DCRs and LTVs use the sum of the amortizing debt service and the unpaid balance of the first loan and all existing and proposed supplemental loans.

Fannie Mae adds a detail that matters for pricing sensitivity. For the supplemental’s own debt service on a fixed-rate loan, the Guide uses an amortizing payment at the greater of the gross note rate or the Underwriting Interest Rate Floor in Form 4660, while the existing loan is tested at its own gross note rate. The first loan’s low coupon therefore helps your coverage, but the new money is sized as if the rate cannot fall below a floor.

The New Loan Test

If the senior loan matures five years or less after the supplemental closes, Fannie Mae’s Guide (Section 1302.03D) requires a New Loan Test. The lender confirms that the combined balance does not exceed what a new fixed-rate, first-lien, cash-out loan would get, tested against Tier 2 requirements with a 10-year maturity. A senior loan with only a few years left can therefore limit proceeds even when the current-rate coverage looks fine. Freddie Mac handles the same concern by capping combined maturity LTV at 70% and by barring supplementals in the last three years.

Value and NOI

Both programs underwrite current performance, not your pro forma. Expect a new appraisal, and expect the lender to re-run NOI with its own management fee and reserve assumptions. The NOI normalization guide shows the usual adjustments. Run your own numbers through the loan sizing calculator, the commercial DSCR calculator and the debt yield calculator before you call the servicer.

Worked example (hypothetical numbers)

The figures below are round, invented numbers for a 60-unit building. They show how the combined tests interact. They are not a quote, a market rate or a real transaction, and they assume a lender grid that allows 70% combined LTV and 1.30x combined DSCR.

Here the LTV test, not coverage, caps the new loan at $1.2 million. The sponsor keeps the 5.00% first loan and pays 6.25% on the new money, for a blended rate of about 5.27%.

Now compare a cash-out refinance of the whole $5.6 million at the same 6.25% rate. Debt service would be about $414,000, which is $42,000 a year more than the supplemental route, and coverage would fall to about 1.26x, below the 1.30x floor assumed above. The refinance would also trigger any prepayment premium on the existing loan. In this scenario the supplemental is both cheaper and easier to size.

Change one input and the result flips. If the appraisal came in at $7,000,000, the 70% test would allow $4,900,000 of total debt, so the supplemental would shrink to about $500,000. A drop in value reduces proceeds dollar for dollar at the top of the stack. To see the dollars on your own loan, use the multifamily mortgage calculator.

Who a supplemental fits

• Your first loan is a Fannie Mae or Freddie Mac loan, with a coupon well below today’s rates that you want to keep.
• At least 12 months have passed since the first loan, and the property is stabilized and performing.
• The senior loan has a meaningful remaining term (Freddie Mac needs three years or more remaining on prior loans).
• You want a defined amount of equity for renovations, reserves or a new acquisition and can live with the combined LTV and DSCR tests.
• You can accept yield maintenance or a graduated premium on the new note. Model it with the yield maintenance calculator and read our prepayment penalties guide.

Who it does not fit

• Owners with non-agency first loans. The programs only attach to their own senior loans.
• Borrowers whose first loan is near maturity. The New Loan Test and Freddie Mac’s three-year bar can limit or block proceeds. A full refinance often makes more sense.
• Sponsors who want to reset the first loan. If you want a lower rate, longer term or new servicer, you are looking at the cash-out refinance route.
• Thin-coverage properties. Combined DSCR must still clear the floor, so a property that barely covers its first loan has little room.
• Heavy business plans. Properties that need lease-up or large renovation before stabilizing usually need bridge financing first.

Supplementals also interact with the rest of your debt strategy. Freddie Mac notes that originating one may trigger collection of deferred reserves and escrows under the first loan, and a later sale will involve both notes. Fannie Mae says supplementals are typically assumable together with the senior loan, subject to review of the new borrower’s financial capacity and experience.

Step-by-step: how to approach a supplemental

1. Pull your first loan documents. Note the lender, the servicer, the maturity date, the coupon and the prepayment schedule.
2. Check timing. Confirm 12 months have passed and the senior loan is not in Freddie Mac’s final three years.
3. Estimate value and NOI. Use a recent appraisal or broker opinion and a lender-style NOI.
4. Size the stack. Run combined LTV and DSCR on the existing plus proposed debt with the loan sizing calculator.
5. Budget costs. Add appraisal, legal, servicer and application fees with the closing cost calculator.
6. Call the servicer, then compare. Ask for a written supplemental quote, and ask what a full refinance would cost. If you want a second opinion, send the scenario through our deal review form.

Questions to ask the servicer

1. What combined LTV and DSCR will you use for my asset class and my use of proceeds?
2. How do you underwrite NOI, management fee and reserves?
3. What is the interest rate, and when can I lock it?
4. What is the prepayment structure, and does its end date match my first loan’s?
5. Which fees and escrows apply, including any deferred reserves on the first loan?
6. Is there a minimum size, and how long does a supplemental take from application to funding?
7. What happens to the supplemental if I sell or refinance the first loan?

Related loan programs

Compare this with Fannie Mae small loans and Freddie Mac Conventional Small for first loans, and with interest-only multifamily loans for how interest-only periods change sizing.

Sources

• Fannie Mae, Multifamily Guide, Part III, Chapter 13: Supplemental Mortgage Loans, Section 1302.03C (Calculating the DSCR and LTV Requirements), accessed October 8, 2026.
• Fannie Mae, Multifamily Guide, Section 1302.03 (Loan Amount) and 1302.03D (New Loan Test), accessed October 8, 2026.
• Fannie Mae supplemental loan term sheet as published by Lument, accessed October 8, 2026.
• Freddie Mac, Optigo Supplemental Loan product sheet, 11/25, accessed October 8, 2026.
• Freddie Mac, Optigo Fixed-Rate Loans product sheet, 4/26, accessed October 8, 2026.

What this page does not do

Multi-Family USA is a lender-matching service operated by LendCity America. It does not originate loans, and nothing here is a commitment or a rate quote. Fannie Mae and Freddie Mac revise their guides and product sheets, and servicers add their own requirements, so verify every figure in a current written term sheet. This content is educational and should be combined with advice from your financing, legal, tax and accounting professionals.

Frequently asked questions