Second charge mortgage growth driven by rate protection – but for how long?

The second charge mortgage market is expanding at a pace not seen for nearly two decades, and the arithmetic behind it is straightforward. A large share of UK homeowners locked in first charge fixes at well below 2% in 2021 and 2022, and they have no intention of surrendering those rates to raise capital. The result, according to one specialist broker, is a market with a single, defining logic.

In the first quarter of 2026, second charge lending reached £625 million across 11,489 new agreements – growth of 33% by value and 22% by volume year-on-year, according to the Finance & Leasing Association (FLA). For 2025 as a whole, new business by both value and volume reached its highest level since 2008.

Joseph Lane (pictured top), founder and director of Mortgage Lane, told Mortgage Introducer the growth reflects a straightforward cost calculation. "Repricing the whole balance at today's rates to access new money is the most expensive way to borrow. So they keep the cheap first charge and take the incremental borrowing as a second charge, even at a far higher rate, because it blends the overall cost down."

He set out the numbers plainly. "Take a borrower with a £300,000 first charge at 1.8% who needs another £100,000. On an interest-only basis, to keep the comparison clean, a full remortgage of £400,000 at 5% costs around £1,667 a month. Keeping the £300,000 at 1.8% and adding a £100,000 second charge at 9% costs around £1,200 a month, a blended rate of roughly 3.6% across the whole £400,000. The headline 9% looks punitive in isolation, but the client is about £5,600 a year better off. That single calculation is the entire second charge market right now."

What is holding borrowers back?

The rate protection story is compelling, but Lane is clear that not every client who would benefit can access it. Affordability is the primary obstacle.

"A second charge is assessed on top of the existing first charge commitment and stressed at a higher rate, so the borrowers who most need the blend are often the ones who cannot evidence it," he said.

Combined loan-to-value (LTV) presents a second constraint. Where house price growth has been flat, the equity headroom needed to support additional borrowing may simply not exist. Client perception is a third barrier, and Lane said it falls squarely on brokers to manage. "You are asking someone paying 1.8% to accept 9%, and that conversation fails unless you lead with the blended cost rather than the headline rate. Where I see it break down is advisers presenting the rate instead of the total cost of borrowing."

Availability narrows further at the specialist end. Complexity in buy-to-let cases, particularly expat borrowers, limited company structures, houses in multiple occupation (HMOs), multi-unit blocks, and larger portfolio cases, reduces the lender panel dramatically. "In the expat and limited company space the panel thins out dramatically, with pricing around 9% to 10%," Lane said. "On HMOs, multi-unit blocks and larger portfolio cases the number of lenders willing to sit behind another charge is very small. The blend has to work considerably harder to justify itself, and in a fair number of cases there is simply no viable second charge route at all, which pushes the client back to a full remortgage they did not want."

What does the market look like beyond 2026?

Lane is measured about the durability of the current growth trend. The sub-2% cohort will not be there indefinitely. "The rate protection driver has a shelf life. As the sub-2% cohort rolls off through 2026 and into 2027, the number of borrowers with a first charge genuinely worth protecting shrinks, and that will take some heat out of volumes."

What follows, in his view, will be structurally different. "What replaces it is affordability. Second charges are increasingly used not because the first charge rate is cheap, but because the borrower cannot raise the money any other way. That is a structurally stickier driver than rate protection."

Consumer Duty is also shaping the market in ways that may prove lasting. "Where a second charge is demonstrably cheaper on a blended basis, not considering it is difficult to defend, and that is pulling more first charge advisers into the space."

Should the Bank of England continue to ease the base rate, Lane expects second charge pricing to follow with a lag. "If base rate eases, second charge pricing will follow with a lag. The blend argument weakens as first charge rates fall, but the early repayment charge avoidance argument does not go away, and that alone will keep this market busy."

With the buy-to-let market already navigating wider political uncertainty, Mendes said the case for brokers pressing lenders on outdated documentation is straightforward. "It's more around brokers having those conversations to make sure clients understand – in the event of a possession situation – what it means."

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