What the proceeds may pay for is the whole definition, and the edges are program-specific. FHA's version of the arithmetic caps the new mortgage at the lesser of the nationwide mortgage limit, the maximum loan-to-value permitted for the transaction, or the sum of existing debt plus allowed costs. Its list of "existing debt" is longer than borrowers expect: the unpaid principal on the first mortgage, the unpaid principal on any purchase-money junior mortgage, the unpaid principal on any junior lien more than twelve months old, interest due, mortgage insurance premium due, prepayment penalties, late charges, and escrow shortages. It also contains a trap for anyone who has drawn on a home equity line recently: where more than $1,000 of a line of credit was advanced within the past twelve months for something other than repairs or rehabilitation of the property, the amount above $1,000 cannot be rolled into the new mortgage. That is HUD Handbook 4000.1, section II.A.8, whose origination pages carry a revision date of 08/14/2019.
The cash-back ceiling is where the definitions actually diverge, and it is the thing to ask about. Both FHA and Fannie Mae accept that estimates of payoffs and costs will not land exactly, and both cap the resulting refund. FHA's limit is $500 at disbursement, and where estimated costs would leave the borrower with more, the mortgagee may reduce the principal balance and submit the loan for endorsement at the lower amount. A refund of the borrower's unused escrow balance from the old mortgage does not count toward that $500. Fannie Mae's limit for a limited cash-out refinance is more generous: cash back to the borrower or any other party that, in aggregate, does not exceed the greater of 1% of the new refinance loan amount or $2,000. Refunds the lender makes for overpaid fees required by law are outside that cap where the settlement statement identifies them.
The consequence of crossing that line is not cosmetic. Once a loan is written as cash-out, it moves to the cash-out loan-to-value ceiling, the cash-out seasoning rules, and cash-out pricing, which is generally worse. Published material on the cash-out refinance covers those rules, including the counterintuitive cases where a borrower who receives nothing at the table is still underwritten as cash-out because of what the proceeds paid off. The practical order of questions is therefore: which category is this loan being written in, then what is the rate.
What Fannie Mae's version also permits. Its acceptable uses reach beyond paying off a first mortgage: paying off an existing home equity line that sits in first-lien position, paying off a construction loan, paying off an installment land contract executed more than twelve months before application, buying out a co-owner under an agreement, and paying off a subordinate lien that was used to purchase the property, where the lender documents that the entire amount of that subordinate financing went to acquire it. That last condition is the reason a second mortgage taken out after the purchase generally cannot be folded in without turning the loan into a cash-out.
Loan-to-value ceilings, and the ratio that is easy to overlook. FHA sets a maximum loan-to-value for a rate-and-term refinance of 97.75 percent for a principal residence the borrower has occupied for the previous twelve months, and 85 percent where the occupancy is shorter or the property is a HUD-approved secondary residence. It separately caps the combined loan-to-value at 97.75 percent, and requires that where a subordinate lien is an open-end line of credit, the maximum accessible credit limit rather than the drawn balance be used in that calculation. Those are program percentages set by policy rather than figures indexed to inflation, and they come from the same 2019-dated handbook section.
The streamlined cousins are different products, not synonyms. FHA's Streamline Refinance refinances an existing FHA-insured mortgage with limited borrower credit documentation and underwriting, in credit-qualifying and non-credit-qualifying versions, and the non-credit-qualifying one requires neither a credit and capacity analysis nor an appraisal. FHA's Simple Refinance is a no-cash-out refinance of an existing FHA-insured mortgage specifically. The Department of Veterans Affairs runs the analogous streamlined program under 38 CFR 36.4307, the interest rate reduction refinancing loan, which requires the new loan to be secured by the same dwelling, the veteran to occupy or have previously occupied it, and either a lower principal-and-interest payment, a shorter term, or a fixed rate replacing a VA-guaranteed adjustable rate.
One tax consequence worth knowing before signing. Under the flush text of Internal Revenue Code section 163(h)(3)(B)(i), a refinancing keeps acquisition character only to the extent the new debt does not exceed the amount refinanced. A straight rate-and-term refinance therefore carries the old character forward, which is one of the quieter advantages of staying inside the category. The mortgage interest deduction page covers the tracing rules in full.