HELOCs are alive and useful. What surprises borrowers is the pricing: prime plus a margin, and the rate floats. A HELOC rate is prime plus a margin, typically somewhere around one to three percentage points depending on how strong your file is. Because the rate floats with prime, a line that looked cheap when you opened it can climb as short-term rates move. Whether that climb matters depends on how large the HELOC is relative to your first mortgage: - Small line behind a big first. Someone with a great low rate on a large first mortgage who borrows a relatively small line, say $25,000, generally does not care much if the HELOC rate moves up a few points. The blended cost across both loans stays low. - Big line behind a small first. When a large second-lien HELOC sits behind a small first-mortgage balance, the line drives most of the total cost. Those are the borrowers who get genuinely shocked. The other group that gets caught off guard: people who set up autopay years ago on an old interest-only second and never looked at the rate again. We have had clients pull their actual loan documents and realize the rate had climbed far more than they assumed. So go in understanding that the line floats, and size it against your first mortgage before deciding whether the rate movement will actually affect you.