Have you been told that a parent can simply "go on the loan" so that you qualify for your first home? If you are a buyer whose income falls short of the payment on a home you can otherwise sustain, that may be true, but FHA and Fannie Mae each attach their own conditions to that parent's income.
The national comparison sites tend to stop at "a co-signer can help," which leaves out the rules that actually decide the file. This guide walks through how each agency counts a non-occupant co-borrower's income and debts, with one worked 2026 example and the governing section cited at each step.
Both agencies add the parent's income and the parent's debts to the file. FHA allows 96.5% LTV for Family Members; Fannie Mae allows 95% in DU and 90% on manually underwritten loans.
What Is A Non-Occupant Co-Borrower?
A non-occupant co-borrower is a person who signs the note and takes on the debt but will not live in the home. Most often that person is a parent, although the two agencies define the relationship and the paperwork differently.
Fannie Mae's Selling Guide B2-2-04 (09/02/2020) describes non-occupant borrowers as credit applicants who sign the note, have joint liability with the borrower, and "may or may not have an ownership interest in the subject property as indicated on the title." These borrowers are permitted on purchase, limited cash-out, and cash-out refinance transactions.
FHA is stricter on title. Under HUD Handbook 4000.1, Section II.A.1.b.ii(A)(4) (Update published August 12, 2026; section dated 11/10/2026), all occupying and non-occupying borrowers must take title in their own name or a living trust at settlement, be obligated on the note, and sign all security instruments.
Keep in mind that FHA treats a co-signer as a separate role. Under Section II.A.1.b.ii(A)(5), a co-signer is liable for the debt and signs the note, but holds no ownership interest and does not sign the security instrument.
In addition, Section II.A.1.b.ii(A)(6) requires non-occupying co-borrowers and co-signers to be United States citizens or to have a principal residence in the U.S. A parent living abroad may want to raise this with the lender before anything else.
How Much Can You Borrow With A Non-Occupant Parent?
The relationship between the borrowers matters a great deal on the FHA side, because the maximum loan-to-value ratio changes with it. On the Fannie Mae side, the underwriting method drives the limit instead.
FHA caps non-occupying borrower purchases at 75% LTV unless the borrowers are Family Members, which lifts the limit to 96.5% on a one-unit home. A family seller who becomes the co-borrower keeps the 75% cap.
The FHA rule sits in Section II.A.2.b.ii(B) (02/16/2021). Here is how that section and Fannie Mae's B2-2-04 set each limit:
| Program and transaction | Maximum LTV | Source |
|---|---|---|
| FHA, Non-Occupying Borrower Transaction | 75% | 4000.1, II.A.2.b.ii(B)(2) |
| FHA, borrowers are Family Members | 96.5%, unless a Family Member is selling to a Family Member who will be a non-occupying co-borrower, or the property has two to four units | 4000.1, II.A.2.b.ii(B)(2) |
| Fannie Mae, manually underwritten | 90% LTV, CLTV, and HCLTV (CLTV up to 105% with a Community Seconds, where the Eligibility Matrix permits) | B2-2-04 |
| Fannie Mae, DU | 95% LTV, CLTV, and HCLTV (CLTV up to 105% with a Community Seconds, where the Eligibility Matrix permits) | B2-2-04 |
That two-to-four-unit carve-out is especially important for family house-hack plans. A parent's income will not carry an FHA duplex above 75% LTV in a non-occupying transaction, and the FHA self-sufficiency test is a separate hurdle on three- and four-unit purchases.
Note that FHA's definition of Family Member, found in the sales-contract provisions of Section II.A.1, is broad. It includes a child, parent, or grandparent (with step and foster relationships), spouse or domestic partner, siblings, uncles and aunts, and in-laws of the borrower.
Conventional buyers should also be aware of B2-1.3-01 (11/05/2025), which states for the 95.01% to 97% LTV tier that "all borrowers must occupy the property unless there is a Community Seconds subordinate lien." That is why the 3% down conventional option generally falls away once a parent joins as a non-occupant.
How The Ratios Are Blended
Lenders often call this a "blended" ratio, while Fannie Mae's own language is "combined qualifying ratios." Either way, the arithmetic is the same: total monthly obligations for all borrowers divided by total qualifying income for all borrowers.
A blended DTI divides the new housing payment plus every borrower's monthly debts by all borrowers' combined qualifying income. The parent's own mortgage counts, which can sharply reduce what that income adds.
Fannie Mae's B3-3.1-01 (10/07/2026) permits non-occupant income for both DU and manually underwritten loans, "provided the income meets the same standards as required for occupying borrowers." In other words, a parent's income receives no shortcut, and the same documentation applies.
For DU, B2-2-04 states that the system considers the income, assets, liabilities, and credit of every borrower, regardless of occupancy. B3-6-02 (04/02/2025) then caps DU files at a 50% DTI ratio.
FHA does not publish a stand-alone blending formula. However, Section II.A.5.d.viii (11/10/2026) excludes non-occupant co-borrower income only for borrowers with no credit score, and that carve-out shows the income otherwise counts; lenders apply the same effective-income standards in Section II.A.4.c (11/10/2026).
A parent who is retired, self-employed, or paid in equity will need to document that income like any other borrower. Our guides to asset depletion income, self-employed income documentation, and RSU income on a mortgage explain how those streams are underwritten.
The Limit Most Families Miss On Manual Underwriting
The largest gap between the two programs appears when a file is manually underwritten. Fannie Mae looks at the occupying borrower alone, and strong combined ratios will not cure a weak result.
On a manually underwritten Fannie Mae loan, the occupying borrower's DTI on their own income may not exceed 43%. This applies even if combined ratios sit well below the standard benchmark.
B2-2-04 states the rule directly: "Using only the income of the occupying borrower(s) to calculate the DTI ratio, the maximum allowable DTI ratio is 43%." B3-6-02 cross-references this limit in its list of exceptions to the general manual ceiling of 36%, or up to 45% with qualifying credit score and reserves.
What's more, the same section requires the occupying borrower to make the first 5% of the down payment from their own funds when non-occupant income is used on a manual file. The exceptions are an LTV or CLTV of 80% or less, or a one-unit principal residence where the borrower meets the requirements to use gifts, donated grant funds, or employer funds.
FHA has no equivalent occupant-only test in the sections reviewed here. Its manual limits instead apply to the file as a whole, per the matrix in Section II.A.5.d.viii, reproduced here:
| Lowest Minimum Decision Credit Score | Maximum qualifying ratios (%) | Acceptable compensating factors |
|---|---|---|
| 500-579 or no credit score | 31/43 | Not applicable; these borrowers may not exceed 31/43. Energy Efficient Homes may have stretch ratios of 33/45. |
| 580 and above | 31/43 | No compensating factors required. Energy Efficient Homes may have stretch ratios of 33/45. |
| 580 and above | 37/47 | One of: verified and documented cash reserves; minimal increase in housing payment; or residual income. |
| 580 and above | 40/40 | No discretionary debt. |
| 580 and above | 40/50 | Two of: verified and documented cash reserves; minimal increase in housing payment; significant additional income not reflected in Effective Income; and/or residual income. |
These limits apply when a file is manually underwritten. Under Section II.A.4.a (11/10/2026), transactions are scored through TOTAL, and an Accept is underwritten under the TOTAL section, while a Refer must be manually underwritten.
A Worked 2026 DTI Example
Consider a daughter buying a one-unit, $400,000 primary residence, with her father as non-occupant co-borrower. All figures below are illustrative: the 6.5% rate, the taxes, the insurance, the private mortgage insurance, and both household budgets are assumptions rather than quotes, and your rate depends on credit, LTV, and term.
Here are the shared inputs:
- Daughter. She earns $4,500 per month in gross qualifying income and carries a $350 car payment.
- Father. He earns $8,000 per month in gross qualifying income, pays $1,900 per month on his own home, and carries a $300 car payment.
- The property. Taxes are assumed at $375 per month and homeowners insurance at $150 per month, on a 30-year fixed loan.
The father's obligations do not disappear because he is not moving in, so the file carries $2,550 per month in other debts. Combined income is $12,500 per month.
Step 1: Confirm The Loan Size
The FHA route uses 96.5% LTV under Section II.A.2.b.ii(B), which produces a $386,000 base loan and a $14,000 minimum investment, matching the 3.5% in Section II.A.2.c.ii (09/14/2015). That base loan sits below FHA's 2026 one-unit floor of $541,287, and you can confirm your county's limit on HUD's lookup.
The conventional route uses the 95% DU maximum under B2-2-04, which produces a $380,000 loan and $20,000 down. That amount is below the 2026 baseline conforming limit of $832,750 set by FHFA.
Step 2: Build The Housing Payment
FHA's total mortgage payment, defined in Section II.A.5.d.vii(B), includes principal and interest, taxes, insurance, and MIP, among other items. Fannie Mae's B3-6-03 (12/16/2020) similarly builds PITIA from principal and interest, insurance premiums including mortgage insurance, and taxes, among other items.
Under Appendix 1.0 (03/20/2023), the upfront premium is 175 basis points and the annual MIP on this file is 55 basis points for the mortgage term, since the base loan is at or below $726,200 with an LTV above 95% and a term over 15 years. Here is the illustrative payment on each route:
| Monthly line (illustrative) | FHA at 96.5% | Fannie Mae DU at 95% |
|---|---|---|
| Loan amount | $392,755 ($386,000 base plus $6,755 financed UFMIP) | $380,000 |
| Principal and interest at 6.5% | $2,482 | $2,402 |
| Mortgage insurance | $177 (approximate annual MIP) | $190 (assumed PMI) |
| Taxes and insurance | $525 | $525 |
| Total housing payment | $3,184 | $3,117 |
Step 3: Run The Ratios
This is where the father's contribution becomes clear. His $8,000 of income arrives together with $2,200 of his own debts, so the file gains $5,800 per month of net capacity rather than the full amount.
| Ratio (illustrative) | FHA at 96.5% | Fannie Mae DU at 95% |
|---|---|---|
| Daughter alone, total DTI | 78.5% | 77.0% |
| Blended housing ratio | 25.5% | 24.9% |
| Blended total DTI | 45.9% | 45.3% |
Step 4: Apply Each Agency's Test
On the FHA side, a blended 25.5%/45.9% fits the 37/47 tier if the file is manually underwritten and documents one compensating factor, such as verified reserves. It exceeds the 31/43 tier, so the outcome rests on the TOTAL finding or that compensating factor.
On the Fannie Mae side, the 45.3% blended DTI sits under the 50% DU maximum, subject to DU's own recommendation. The manual route, however, is closed: at 77.0% on her income alone, the daughter is far beyond the 43% occupant test, and $4,500 of income supports only about $1,585 in housing payment after her car loan.
The takeaway for this family is that the parent's income may carry a DU or TOTAL approval, but a manual downgrade plays out very differently under each agency. Accordingly, you may want to ask your lender which finding the file received before you rely on either route.
Which Credit Score Applies?
Adding a parent with excellent credit does not raise the score used to qualify the loan. Both agencies generally anchor to the weaker borrower, although Fannie Mae has one notable exception.
FHA takes each borrower's Minimum Decision Credit Score and uses the lowest. Fannie Mae also uses the lowest for its representative score, though certain manual files average each borrower's median score.
Under Section II.A.1.b.ii(A)(3), the FHA credit score is the lowest among all borrowers, and under Section II.A.2.b.i an MDCS of 580 or above is eligible for maximum financing, while 500 to 579 is limited to 90% LTV. A file in which an occupying borrower has a 640 and a parent has a 780 is therefore a 640 file.
Fannie Mae's B3-5.1-02 (04/22/2026) selects the lowest applicable score as the representative score, which Fannie Mae also uses for loan-level price adjustments on all loans. For certain manually underwritten transactions, the average median credit score is used to test the minimum score, which can help a thin-file buyer clear that floor without changing pricing.
Minimum credit score and reserve requirements on manual files are based on the LTV and combined ratios per Fannie Mae's Eligibility Matrix. Confirm the current tier with your lender, since the matrix governs those figures.
What This Means For The Parent
A parent who signs takes on the full debt. Both agencies treat the parent as obligated on the note, so a missed payment by the child remains the parent's liability too.
FHA does address what happens next. Under the exceptions in Section II.A.1.b.ii, a non-occupying co-borrower on an existing FHA-insured mortgage may qualify for another FHA-insured mortgage on a new property as their own principal residence, and a borrower with an FHA loan on their own home may qualify as a non-occupying co-borrower on other FHA-insured mortgages.
On a Fannie Mae loan, title is optional for the non-occupant, which may matter for a family thinking about estate planning or a later buyout of an inherited home. You may want to consider speaking with an attorney about how title should be held, since those consequences fall outside the underwriting guidelines.
Questions To Bring To Your Lender
Non-occupant files vary, and lenders may apply overlays stricter than the agency minimums. Here is a list of the items worth settling early:
- Underwriting path. Ask whether the file is expected to receive a DU approval or a TOTAL Accept, and what happens to the structure if it is downgraded to manual.
- Family relationship. Confirm that the co-borrower meets FHA's Family Member definition, particularly on anything other than a parent-child purchase.
- Seller relationship. If a relative is selling the home, raise it at once, since a Family Member seller who becomes the co-borrower returns the file to 75% LTV.
- Parent's debts. Have the parent's full housing payment and installment debts ready, because those figures decide whether the blended ratio improves enough.
All of these points come down to one question: does the parent's net capacity, after their own obligations, move the file inside the limit that applies to your underwriting path? Running the numbers with your real figures before you make an offer will answer that far better than any rule of thumb.
A licensed loan officer who has closed non-occupant files can test both routes against current guidelines. Because the Selling Guide and Handbook 4000.1 are revised regularly, ask them to confirm the sections above remain current for your application date.
This article is for informational purposes and is not financial or mortgage advice. Consult a licensed professional in your jurisdiction.