Consider the borrower. Net worth in eight figures. Income arriving in three currencies across two companies and a trust. A property portfolio that services itself. On any measure of actual financial resilience, this is a low-risk client. On a standardised affordability template built around a single PAYE salary in sterling, they can look unaffordable. 

This is the gap CP26/18 starts to close. The current rules were calibrated for the median borrower, which is exactly what a regulator protecting a whole market should do. But "calibrated for the median" means "awkward for the exception," and high-net-worth and internationally mobile clients are nothing but exceptions. Their wealth is real. Their income is lumpy. Their structures are complex. None of that is a credit risk. It is simply a poor fit for a tick-box.

The proposals on variable and irregular income matter here. So does the explicit attention to foreign currency loans. Read through the HNW lens, the FCA is not lowering the bar. It acknowledges that the bar was measuring the wrong thing for a particular kind of borrower.

Foreign currency lending is the proposal I would watch most closely.

A founder sells a US business and is paid in dollars. An executive relocates to Dubai on a dirham package. A family's wealth sits in euros, and they want to buy in London. Under the existing approach, currency mismatch between income and loan introduces friction that has pushed much of this lending toward private banks and a narrow set of specialist lenders willing to underwrite it manually.

If the FCA reduces the barriers to lending against foreign currency income, the pool of lenders prepared to engage should widen. More competition for these clients means better terms and, just as importantly, more certainty. For internationally mobile borrowers, certainty of execution is frequently worth more than a few basis points on the rate. A deal that completes on time beats a marginally cheaper deal that collapses at underwriting. I would not overstate it yet. This is a consultation, not a rulebook, and lenders will move at their own pace once final rules land. But the direction is clear, and the direction favours exactly the cross-border client the UK has spent a decade making to feel like a problem to be solved rather than a customer to be won.

The interest-only proposals are the third piece, and they are more interesting than they sound.

Interest-only loans acquired a reputation problem after the financial crisis, much of it deserved at the mass-market level, where borrowers held interest-only loans with no credible plan to repay the capital. The FCA is proposing more flexibility while still requiring most borrowers to have a clear repayment strategy, with some latitude for smaller loans.

For sophisticated borrowers, interest-only was never a mass-market problem. It is a capital efficiency tool. A client with substantial liquid assets may rationally choose to service interest and retain capital for higher-returning uses, with a defined exit through asset sale, business event, or refinance. That is not recklessness. It is treasury management applied to a home. The proposed changes, alongside the updates to retirement interest-only lending, give lenders more room to recognise that distinction instead of treating every interest-only request as a relic.

Take a client, we will call the returning founder. He spent eight years building and selling a technology company in California. He is moving back to London, buying a family home in the £6 million range. His liquid wealth is considerable but mostly held in dollars and partly tied up in an earn-out that pays over three years.

Under today's rules, three separate frictions stack up. His income is in foreign currency. It is irregular, weighted toward future earn-out payments. And the loan structure that suits him best is interest-only, because forcing capital repayment would mean liquidating dollar assets at a moment he would rather not. Each friction is individually surmountable. Together, they narrow his options to a handful of lenders and lengthen every conversation.

CP26/18 touches all three. It does not guarantee him a better outcome, and his affordability still has to be demonstrated. But it moves each of those three frictions in his favour at the same time. That is the quiet significance of this paper for the top of the market: it does not solve one problem for these clients. It softens several at once.

Nothing has changed yet. These are proposals. The consultation runs until 28 July 2026, final rules are expected later in the year, and lenders will then decide individually how far to flex. Anyone reading this as "the rules just got easier" is a year ahead of the facts.

What has changed is the trajectory. The regulator has signalled that it wants a market that can accommodate income that is variable, international, and complex, while keeping affordability discipline intact. For borrowers whose financial lives have never fit a template, that signal is the most encouraging thing to come out of the FCA's mortgage work in years.

The headlines belong to first-time buyers. The structural shift belongs to everyone. The standard model was quietly turning away.

The views expressed here are my own and reflect my reading of an open FCA consultation as of June 2026. They do not constitute financial, legal, or regulatory advice. CP26/18 is a consultation, and its proposals are not in force; rules may change before they are finalised. Enness is a finance broker, not a lender. Anyone considering a mortgage or borrowing decision should seek professional advice specific to their circumstances. Your home may be repossessed if you do not keep up repayments on a mortgage or other debt secured on it.