The Assumable Mortgage Equity Gap: How to Cover It

Where the gap comes from

Assuming a mortgage means taking over the seller's loan as it stands: the same balance, rate and remaining term. Most FHA and VA loans can be assumed with the servicer's approval; most conventional loans can't, because their due-on-sale clause lets the lender call the loan when the home is sold. The loan you take over covers only what the seller still owes. Everything above that, the seller's equity, you pay at closing.

That is the equity gap, and it can be large: a seller who bought years ago has often paid the balance down and seen the home's value rise. In the example below, a $420,000 home with $280,000 owed has a gap of $140,000.00, 33% of the price.

Why the gap changes the math: the blended rate

Whatever part of the gap you don't pay in cash has to be borrowed, usually on a second mortgage behind the assumed loan, which often costs more than a first mortgage. What you really pay is the blended rate across both loans:

BB

Balance of the assumed loan

SS

Second loan covering the rest of the gap

r_1, r_2r_1, r_2

Rates on the assumed loan and the second loan

In the example the buyer has $45,000 of cash, so after the processing fee a 20-year second loan at 8.75% covers $95,000.00. The blended rate is 4.46%, against 6.5% on a new 30-year loan for the whole purchase. Assuming saves $83,004.69 of interest over ten years, and the monthly payment is $232.94 lower, partly because both loans pay off sooner than a new 30-year loan.

How the size of the assumable mortgage equity gap changes the result

Here is the same home and buyer with the seller owing more or less:

Every dollar the seller owes is a dollar at the low assumed rate; every dollar of gap is either your cash or borrowed at the second loan's rate. As the gap grows, the blended rate climbs toward the second loan's rate and the savings shrink.

The second-loan rate that breaks even

Because the second loan carries the gap, its rate is the number to negotiate. In the example, assuming still saves interest over ten years with a second loan at up to about 17.3%; above that, the new loan costs less over the decade. Run the same search for your deal by changing the second loan's rate in the assumable mortgage calculator until the savings reach zero.

The term matters too. A shorter second loan raises the monthly payment but clears the expensive debt sooner; a longer one keeps the payment down but pays its higher rate for longer.

Mortgage insurance belongs in the comparison as well. FHA mortgage insurance stays with an assumed FHA loan, so the seller's monthly premium becomes yours; ask for a recent statement that shows it. A new loan with less than 20% down usually carries mortgage insurance of its own. The example includes $120 a month on the assumed loan and $150 on the new one, and the calculator lets you enter your own figures for both.

Ways to cover the gap

• Cash. The cheapest source, if you have it. Cash that goes into the gap isn't available for reserves or repairs, so keep enough back.
• A second mortgage. A closed-end second loan or a home equity line of credit on the home you are buying, behind the assumed loan. Ask lenders early whether they will lend behind an assumed FHA or VA loan, since not all do, and get the rate and term in writing.
• A seller note. A seller with enough equity may carry part of the gap as a note, paid monthly. The seller financing calculator works out the payment and any balloon, and the note's rate goes into the blended rate like any other second loan.
• A lower price. Offering less narrows the gap directly, dollar for dollar; it is a negotiation like any other.

Whatever the mix, the servicer of the assumed loan has to approve the assumption, and you have to pass its credit review. FHA lets the servicer charge a processing fee of up to $1,800; VA caps its processing fee at $300 and charges a funding fee of 0.5% of the balance unless you're exempt.

Before you make an offer

Get the seller's current balance, rate, remaining term and any mortgage insurance from a recent statement, not the original loan amount. Price the second loan before you write the offer, since it decides whether the deal works. Compare the blended rate and the interest over the years you expect to keep the home with a new loan at today's rate, and make sure the combined monthly payment fits your budget. Then confirm with the servicer that the loan is assumable and how long approval takes, because assumptions take longer to close than a new loan.

VA loans: entitlement and the funding fee

A VA loan adds two questions that an FHA loan doesn't. First, the seller's VA entitlement stays tied to the loan after the sale unless the buyer is an eligible veteran who will live in the home and substitutes their own entitlement; only then is the seller's restored. That can matter to a seller who wants to use VA financing again.

Second, the buyer pays VA a funding fee of 0.5% of the balance assumed, unless exempt. On the example's balance that would be $1,400.00. It adds to the cash you need at closing alongside the equity gap itself, so count it when you work out how much of the gap your cash can cover.