Junior lien position is the risk the rate is compensating for, and it matters in two situations. Lien priority determines who is paid from a forced sale. In a foreclosure the first mortgage is satisfied in full before the second lender receives anything, so if the property sells for less than the first balance plus costs, the second lender recovers nothing on its security. Two consequences follow for the borrower. A second-lien rate is higher than a first-mortgage rate on the same property because of that exposure. And in a short sale, where the price is less than the total owed, the junior lienholder has to agree to release its lien for a partial payment or the sale cannot close, which gives it a practical veto out of proportion to its share of the debt. A borrower who defaults can also be foreclosed by a junior lender, subject to the first mortgage.
Regulation Z splits the two instruments cleanly, and the split is not cosmetic. 12 CFR 1026.40 opens by stating that "the requirements of this section apply to open-end credit plans secured by the consumer's dwelling." Everything in that section is therefore unavailable on a closed-end home equity loan: the application-time disclosures and the brochure, the bar on a nonrefundable fee within three business days of receiving them, the refund of application fees if a disclosed term changes before the plan opens, the requirement that any rate change follow a public index outside the creditor's control, and the limits on when a creditor may terminate or freeze the credit. A closed-end home equity loan gets the ordinary closed-end regime instead, which means the 1026.18 disclosures, including the annual percentage rate, the finance charge, the total of payments and a statement of whether a prepayment charge applies. Neither set is better; they are different, and knowing which one governs tells you which protections you have.
The three-day right to rescind is real here and does not exist on a purchase mortgage. 12 CFR 1026.23(a)(1) gives a right of rescission in any credit transaction in which a security interest is retained or acquired in the consumer's principal dwelling, to each consumer whose ownership interest is subject to that security interest. 1026.23(f)(1) then exempts a "residential mortgage transaction," which 1026.2(a)(24) defines as financing the acquisition or initial construction of the dwelling. A home equity loan is not financing the purchase, so it is inside the right and a purchase mortgage is outside it. Three details are worth carrying: the clock runs to midnight of the third business day after the later of consummation, delivery of the rescission notice, and delivery of all material disclosures; the notice must be given in writing, because 1026.23(a)(2) requires mail, telegram or other written communication; and where more than one consumer holds the right, exercise by one is effective as to all. Note also the limitation to a principal dwelling, so a loan against a second home or a rental does not carry it. This is a different three-day period from the one a homebuyer gets to read a Closing Disclosure, and the two are frequently conflated.
The tax treatment, by the route rather than by the conclusion. The outcome is usually reported correctly and the reasoning behind it usually is not, and the reasoning is what stops a reader drawing the wrong inference. There is no exception allowing home equity interest where the money improves the home. IRC 163(h)(3)(F)(i)(I) switches the home equity limb off entirely, and borrowing used "in acquiring, constructing, or substantially improving any qualified residence of the taxpayer" and "secured by such residence" is acquisition indebtedness in the first place, under IRC 163(h)(3)(B)(i). So the product label never controls the answer; the use of the money does. A "home equity loan" that funds a new roof is acquisition debt and its interest is qualified residence interest; the identical loan used to clear credit cards is home equity indebtedness and its interest is not deductible at all.
Two consequences the label-based version hides. First, because qualifying borrowing is acquisition debt, it counts against the acquisition debt cap, which is $750,000 of aggregate acquisition indebtedness, or $375,000 for a married person filing separately, shared with the existing mortgage rather than sitting alongside it. Debt taken on before December 16, 2017 keeps a grandfathered $1 million limit. Second, this is deductible only as an itemized deduction, so it is worth nothing to a household taking the standard deduction.
Two things changed in 2025, so anything written before then describes a system that no longer exists. The disallowance and the $750,000 cap were originally written to lapse after 2025, which is why a reader may well have been told that the home equity deduction returns afterward. It does not. Public Law 119-21 section 70108(a)(1)(A) struck the words ", and before January 1, 2026" from IRC 163(h)(3)(F)(i), and section 70108(a)(3) rewrote the paragraph's heading to read "Special rules for taxable years beginning after 2017." Both are therefore permanent, with no end date. Running the other way, section 70108(a)(1)(B) added IRC 163(h)(3)(F)(i)(III), which switches off the clause that had terminated the mortgage insurance premium deduction after 2021, so qualified mortgage insurance premiums are treated as qualified residence interest again, for taxable years beginning after December 31, 2025.