The mechanics
A low-rate mortgage can change hands. Here's the math.
Assumption is one of the few ways a buyer can inherit a rate from 2020-2022. The trick is financing the seller's equity without giving up the benefit of the first loan.
1. Assumable first mortgage
The buyer takes over the seller's existing government-backed loan at its original note rate. The servicer underwrites the buyer the same way it would a new borrower.
2. Second lien for the equity gap
The difference between the loan balance and the purchase price, minus the buyer's cash, is financed as a HELOC or piggyback second at current home-equity rates.
3. Buyer cash at closing
Cash covers the down payment, closing costs, and any difference the second lien doesn't finance.
The formula
blended rate = [ (loan₁ × rate₁) + (loan₂ × rate₂) ] ÷ (loan₁ + loan₂)
For a $500,000 purchase: $300,000 assumed at 3.25% plus a $100,000 second at 8.50% on $400,000 financed yields a 4.56% blended rate, versus 6.75% for a standard loan.
Blended rate calculator
$500,000 home
Today's typical home-equity second for an equity gap.
Your blended rate (est.)
5.61%
Market
7.18%
Estimated monthly savings
$342
$4,105 a year versus a 7.18% market loan.
Estimates only. Blended rates are balance-weighted and exclude taxes, insurance, and fees. Assumption and second-lien financing require servicer underwriting, a credit review, and approval. The rate shown is the assumed loan rate, per seller — not an offer, and not a quote from listmyrate.
From request to closing
01
Request
Buyer sends a request with down payment, credit band, and timeline.
02
Seller approval
Seller reviews and authorizes release of servicer details.
03
Servicer application
The assumption package is submitted to the servicer.
04
Underwriting
Buyer is underwritten for the assumed loan and the second lien.
05
Closing
Title transfers, the first loan is assumed, and the second lien funds.
Compliance guardrails
TILA & RESPA
Every calculator result is labeled an estimate. Loan assumptions and second liens require servicer underwriting, a credit review, and approval. No figure shown here is an offer of credit, and any rate shown is the assumed loan rate, per seller.
Fair Housing Act
Listing copy is screened against a discriminatory-language list before publication, and sellers cannot publish a listing with flagged phrases.
Seller consent & authorization
Servicer names and loan details are shared only with the seller's explicit authorization, and only after a buyer request is approved.
Data handling
Buyer contact details and financing information are visible to the listing's seller and platform administrators only, never to other marketplace users.
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Questions about how assumption works? Email support@listmyrate.com.