PIGGYBACK LOANS · LAST VERIFIED APRIL 2026

Piggyback Loans: 80/10/10 and 80/15/5 Structures Explained (2026)

Q: What is an 80/10/10 piggyback loan?

An 80/10/10 piggyback involves a primary mortgage covering 80% of the home price, a second loan (usually a HELOC) covering 10%, and a 10% down payment from the buyer. The structure avoids private mortgage insurance (PMI), which is required when the primary mortgage exceeds 80% of home value. The HELOC second lien is typically at a higher rate than the first mortgage.

Q: When does a piggyback beat PMI?

A piggyback beats PMI when the cost of the second HELOC lien is lower than the PMI premium. At April 2026 rates, a typical HELOC margin of 2.75% over prime (total ~10.00% APR) on the 10% second lien often costs less than PMI at 0.8-1.2% of the full loan amount annually. The break-even depends on your specific PMI rate, HELOC margin, and how quickly you build equity.

Q: Is HELOC interest on a piggyback tax deductible?

Yes, if the HELOC is used to acquire the home. Under post-TCJA rules, HELOC interest is deductible as mortgage interest if the funds are used to buy, build, or substantially improve the residence securing the loan. A piggyback HELOC used at purchase meets this requirement, subject to the $750,000 combined mortgage debt cap.

Piggyback structures combine a primary mortgage with a HELOC second lien, letting you put 10% down while avoiding private mortgage insurance. Here is how the structures work, when they beat PMI, and lender acceptance in 2026.

80/10/10 Structure Visualised

80/10/10 Mechanics

80% primary mortgage (fixed-rate, conventional). 10% second lien (HELOC, variable rate, prime + margin). 10% down payment from buyer.

Because the primary mortgage covers only 80% of the purchase price, it stays below the PMI threshold. The second lien is a HELOC on which you typically make interest-only payments during the draw period.

The HELOC second lien is typically paid off aggressively or refinanced away once the primary mortgage balance drops below 80% through payments, equity growth, or both.

80/15/5 Mechanics

80% primary mortgage + 15% second lien + 5% down payment. Higher leverage, harder to qualify for. Requires exceptional credit (typically 720+) and a lender willing to accept 5% down with a second lien.

Availability declined significantly post-2008. Some credit unions and portfolio lenders still offer it. National banks generally do not.

The larger second lien (15%) means higher variable-rate exposure on the HELOC portion. Rate risk management is more important in this structure.

Piggyback vs PMI Calculator

Compare the monthly cost of a piggyback structure vs a single mortgage with PMI.

Home price ($)

Down payment (%)

First mortgage rate (%)

HELOC margin (%)

PMI rate (annual %)

Piggyback 80/10/10

First mortgage: $320,000

HELOC: $40,000 @ 10.00%

$2516/mo

No PMI

Single mortgage + PMI

Loan: $360,000 @ 7.25%

PMI: $240/mo (0.80%)

$2696/mo

Piggyback saves $180/month vs PMI path

Note: PMI can be cancelled once equity reaches 20%. HELOC interest rates are variable and may increase.

Risks and Considerations

Two loans, two sets of payments

You are managing two separate lenders, two payment schedules, and two interest rates. If you struggle financially, both must be serviced.

HELOC variable-rate risk on second lien

The second lien is at variable rate. If prime rises 200bp, the HELOC payment on the 10% second lien rises accordingly. Model your payment at prime + 300bp before committing.

Combined DTI impact

Underwriters count both loan payments in your debt-to-income ratio. The second HELOC lien adds to your DTI even if interest-only.

Lender acceptance varies

Not all primary mortgage lenders accept simultaneous second liens from other lenders. Confirm acceptance before committing to a specific primary lender.

FAQ

What is an 80/10/10 piggyback loan?+

A primary mortgage covering 80% of home price, a second HELOC covering 10%, and a 10% down payment. Avoids PMI because the primary mortgage stays at 80% LTV.

When does a piggyback beat PMI?+

When the cost of the second HELOC lien is lower than the PMI premium. At April 2026 rates, a HELOC at ~10% APR on 10% of a $400k home costs $333/month. PMI at 0.8% on the full $380k mortgage costs $253/month. In this example, PMI is cheaper.

Is HELOC interest on a piggyback tax deductible?+

Yes, if the HELOC is used to acquire the home (which a piggyback HELOC is). Subject to the $750k combined debt cap. See /tax-treatment-detailed.

Can I pay off the HELOC second lien early?+

Yes, and it is often the smart move once you build equity. Check for prepayment penalties. See /early-payoff-penalties.

Related: Tax Treatment · Rate Math · Lender Shootout · Fees · Home