Can a Piggyback HELOC Help You Avoid PMI on a Refinance?
Refinancing sometimes runs into an unwelcome surprise: even with real equity built up, the new loan amount can land just short of the cutoff that would avoid paying for mortgage insurance. Splitting the refinance into two loans is one way some homeowners try to close that gap.
The short answer
A piggyback HELOC pairs a primary refinance loan with a second, smaller home equity line of credit, structured so the first loan’s balance stays under the loan-to-value threshold that normally triggers private mortgage insurance. Instead of paying for that insurance, the borrower pays interest on the second loan. Whether the trade actually saves money depends on the HELOC’s rate, any fees involved, and how quickly the second loan gets paid down.
Why mortgage insurance enters the picture
Lenders generally require private mortgage insurance when a loan represents a large share of the home’s value, since it protects the lender if the borrower defaults and the home doesn’t sell for enough to cover the balance. The exact cutoff is commonly cited as a loan sitting at or above a certain loan-to-value ratio, though the specific threshold and rules can vary by lender and loan type and are worth confirming directly rather than assumed from a rule of thumb.
How the split structure works
Rather than refinancing with a single loan that crosses the mortgage-insurance threshold, the homeowner takes out a first loan sized to stay comfortably under it, then covers the remaining amount needed with a second loan — the HELOC — layered on top. This structure is sometimes described using shorthand like an 80-10-10 arrangement, referring to the rough split between the first loan, the second loan, and the homeowner’s own equity; the general mechanics are covered in more depth in how a piggyback loan is structured.
Weighing the actual tradeoff
- Mortgage insurance cost. Typically a recurring charge added to the monthly payment for as long as the loan-to-value ratio stays above the threshold, which can run for years depending on how quickly the home is paid down or how much it appreciates.
- HELOC interest cost. Usually a variable rate applied to the second loan’s balance, which can rise or fall over time and is paid regardless of the home’s loan-to-value ratio.
- Extra closing costs. Two loans generally mean two sets of fees, which eats into any savings the structure is meant to produce.
The comparison isn’t automatic in either direction — it depends on the size of the gap being closed, the rate on the second loan, and how long the homeowner expects to keep the property.
Where this approach tends to fit
The math tends to favor a piggyback structure more clearly on larger loan amounts, where the dollar cost of ongoing mortgage insurance is substantial enough to outweigh the added complexity and fees of a second loan. On a smaller gap, the extra paperwork and closing costs of running two loans instead of one can offset much of the intended savings.
A practical habit
Before choosing a piggyback structure over simply paying for mortgage insurance, it helps to write out the total expected cost of each path over a realistic time horizon — insurance payments on one side, second-loan interest and fees on the other — rather than comparing the monthly payment alone.