On an FHA loan, a non-occupant co-borrower caps the loan at 75% of value. If that co-borrower fits HUD's definition of a Family Member, the cap goes back to 96.5%. On a $700,000 purchase that single word is the difference between putting down $175,000 and putting down $24,500. HUD Handbook 4000.1 states it directly: for non-occupying borrower transactions the maximum loan-to-value is 75 percent, and it "can be increased to a maximum of 96.5 percent if the Borrowers are Family Members."
I have been licensed since November 2001 with more than 1,100 transactions across the five boroughs, and the second signature is the part of a deal that buyers arrange last and should arrange first. By the time somebody asks me whether their brother can help, they have usually already picked a building, and in a co-op the building is the constraint that decides everything else.
The existing guide to parents cosigning covers the common case. This one covers the three that are not: a sibling, an adult child buying for an aging parent, and someone with no family relationship at all.
Three roles that get used as if they were one
| Role | Signs the note | On title | Lives there |
|---|---|---|---|
| Co-borrower | Yes | Yes | Yes |
| Non-occupant co-borrower | Yes | Usually, and always on FHA | No |
| Cosigner or guarantor | Yes | No | No |
The Federal Trade Commission draws the line usefully: a cosigner "receives no tangible benefit from the agreement, but undertakes liability as a favor to the main debtor who would not otherwise qualify for credit." That is the whole risk in one sentence. A cosigner carries the debt and owns nothing.
Under Fannie Mae's rules, guarantors and cosigners do not hold an ownership interest in the property but sign the note and take joint liability for it, while a non-occupant borrower signs the note and may or may not be on title. FHA is stricter: every occupying and non-occupying borrower must take title in their own name or a living trust and sign all the security instruments, while an FHA cosigner signs the note only. That distinction matters because FHA's 75% penalty keys off borrowers, so the two roles are not interchangeable.
Does the relationship matter? It depends entirely on the loan
This is the question everyone asks and almost every answer online gets half right, because the answer is different for each of the four loan types.
| Loan | Non-occupant allowed | Family relationship required | Max LTV |
|---|---|---|---|
| Fannie Mae | Yes | No | 95% through automated underwriting, 90% manual |
| Freddie Mac | Yes | No | 95% with an Accept, 90% manual |
| FHA | Yes | Not required, but it sets the cap | 96.5% for a Family Member, otherwise 75% |
| USDA | Effectively no | Not applicable | All applicants must occupy |
Neither the Fannie nor the Freddie section conditions eligibility on a family relationship. The only relationship bar in both is that the non-occupant cannot be an interested party to the sale, meaning not the seller, the builder, or the agent. So on a conventional loan an unrelated friend is, on paper, no different from a brother. VA sits apart: a loan to a veteran plus a non-veteran who is not the spouse is a joint loan requiring the Secretary's prior approval, with the guaranty computed only on the veteran's portion.
HUD's Family Member list is wider than people assume
If FHA is in play, this list is worth money. HUD's definition covers a child, parent, or grandparent, including step and foster relations, a spouse or domestic partner, a legally adopted child, a foster child, a brother or stepbrother, a sister or stepsister, an uncle, an aunt, and son-in-law, daughter-in-law, father-in-law, mother-in-law, brother-in-law, or sister-in-law.
So a sibling qualifies for the 96.5% treatment. An aunt qualifies. A brother-in-law qualifies. A cousin does not. A niece or nephew does not. A friend does not, and neither does an unmarried partner who is not a domestic partner. Those all land at 75%, which on most NYC price points is not a loan anybody was planning to make. Two exclusions apply even between family: a Family Member selling to a Family Member who will be a non-occupying co-borrower, and any two to four unit property.
The adult child buying for an aging parent
This scenario has a rule written specifically for it, and it is more generous than buyers expect. Fannie Mae's occupancy guidance says that where children want to provide housing for parents, if the parent cannot work or lacks sufficient income to qualify on their own, the child is considered the owner occupant. Freddie Mac reaches the same result from the other direction, treating the property as a primary residence when it is occupied by the borrower's parent. That means primary residence pricing and primary residence down payment rather than investment property terms.
In a co-op, the answer depends on which borough you are in
The financing is the easy half. The proprietary lease is the hard half, and New York's appellate courts are split on it. The standard occupancy clause lets family members live in the apartment, and the First Department, which covers Manhattan and the Bronx, has read that to permit family occupancy only while the shareholder is also living there. The Second Department, covering Brooklyn, Queens and Staten Island, has read it the other way.
Read that against the plan. An adult child buying a Manhattan co-op so a parent can live in it alone is the exact fact pattern the First Department treats as a lease violation without board consent. This is not a reason to abandon the idea. It is a reason to get the board's written consent up front, in that borough especially, and to consider whether a condo is the cleaner structure. The condo versus co-op comparison works through the same board mechanics in the other direction, parent buying for child, and the tradeoffs are the mirror image.
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Where a second signature on the loan changes what you can reach
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Siblings and unrelated guarantors in a co-op
Everything in this section is how NYC boards generally operate rather than law. No statute governs whether a board accepts a guarantor. Each corporation sets its own policy in its bylaws, its proprietary lease, and board resolutions, so the only reliable answer comes from the managing agent for that specific building.
With that said, the practical ranking is consistent. A sibling co-purchaser where both parties are on the stock and lease is the most workable of the three, because it is the same structure a board already understands from co-purchasing couples. A guarantor is accepted only where the building permits guarantors at all, and many do not; where they are permitted, practitioners describe boards expecting the guarantor to be strong enough to carry the apartment on their own and to submit the same complete file the purchaser does, including a REBNY financial statement. A guarantor with no family relationship is the hardest ask of the three, and the honest answer is that plenty of buildings will simply decline.
One piece of sequencing that saves deals: ask the managing agent about guarantors and non-occupant co-purchasers before you see the apartment, not after the offer is accepted. It is a two-minute question, and a no is far cheaper in week one. Whatever the structure, the file itself is the same document by document, which the board package checklist lays out.
What the second signer is actually agreeing to
Whoever signs deserves a straight explanation, so give them this one before they sign rather than after.
What they take on
- Full liability for the whole debt, not a share of it
- The loan on their credit report, missed payments included
- The payment counted in their own debt-to-income ratio
- No ownership at all if they are a cosigner rather than a co-borrower
How it comes back off later
- Fannie Mae lets a lender exclude a mortgage someone else pays
- Requires twelve months of cancelled checks or bank statements
- Requires no delinquencies in those twelve months
- FHA has a parallel contingent liability rule with a twelve month test
That exclusion rule is the answer to the question every sibling asks, which is whether this blocks them from buying their own place. It does not permanently, but it does for the first year, and it only clears if the payments were made on time and documented. Say that plainly up front, because a family member who finds out at their own preapproval is a family problem, not a lending problem.
One protection worth knowing. Under Regulation B a lender cannot require a cosigner at all if you qualify on your own standards of creditworthiness, and where an additional party genuinely is needed, the lender may ask for a cosigner but cannot require that it be your spouse. If a loan officer tells you your spouse specifically has to sign, that is worth a second opinion.
Putting a relative on title is a gift
Adding a sibling or any other non-spouse to the deed without receiving anything for it is a gift of the interest transferred, because the IRS treats any transfer where full consideration is not received in return as a gift. The 2026 annual exclusion is $19,000 per recipient, or $38,000 from a married couple splitting gifts, and above that the donor files Form 709. Filing a return is not the same as paying tax, since the excess ordinarily just reduces the lifetime exemption, which sits at $15,000,000 per person in 2026. Valuing a fractional interest in an apartment is genuinely a job for a CPA rather than a rule of thumb, so get one involved before the deed is drawn, not after. Gifting a down payment covers the documentation side.
Everything on this site about cash, gifts, trusts, and inherited money
Open the SectionBuying with help from someone who is not a parent?
Milton Coste, Licensed Real Estate Associate Broker, licensed since November 2001 with more than 1,100 transactions across all five boroughs. Tell me who is signing and what you are looking at, and I will find out what that building actually allows before you fall for an apartment.
Ask MiltonThis is planning context, not legal, tax, or lending advice, and program rules change. Lending citations are to HUD Handbook 4000.1 section II.A, the Fannie Mae Selling Guide sections B2-1.1-01, B2-2-04 and B3-6-05, the Freddie Mac Guide sections 4201.11 and 5103.1, 38 CFR 36.4308, and Regulation B at 12 CFR 1002.7(d), all as of August 20, 2026. The 2026 gift tax figures are the annual exclusion of $19,000 per recipient and the lifetime exemption of $15,000,000 per person. The appellate split described is between the First and Second Departments on the standard proprietary lease occupancy clause, and the outcome in any dispute depends on the specific lease language and facts. Co-op board practice is set by each cooperative corporation and varies widely. Confirm your own position with a New York real estate attorney, a lender, and a CPA before signing.
