£5m+ Mortgages Rise to 333. Why Wealthy Property Buyers Are Still Choosing Debt

A client can afford a £12m house in cash and still decide that a £5m, £8m or larger mortgage is the more appropriate structure. At this end of the market, debt may preserve liquidity, avoid an immediate investment sale or spread risk across property and financial assets, but the result depends on the total cost, collateral and flexibility of the facility.

Mortgage Introducer reported on 24 September that 333 regulated UK residential mortgages of £5m or more were completed in the year to 31 March 2026, up from 313 in the preceding year. The updated FCA-derived figures were supplied to Karis Capital.

The combined value was approximately £3.3bn, implying an average advance close to £10m. London accounted for 292 cases—88% of the total—while only eight were secured on properties outside London, the South East and the South West.

The distinction between the sources matters. The FCA’s published Freedom of Information table records 313 regulated mortgage sales worth £2.901bn for Q2 2024 to Q1 2025. Its next column only covered Q2 to Q4 2025 because Q1 2026 was not available when the data was released. The 333 figure therefore comes from the subsequently updated data reported through Karis, rather than from the earlier table as displayed on the FCA website.

The figures cover regulated mortgage sales with advances of at least £5m. They do not represent every super-prime property loan. Unregulated investment lending, company borrowing, bridging and other facilities may sit outside the dataset.

A £5m Mortgage Does Not Mean the Client Lacks £5m

The ordinary mortgage story begins with a buyer who needs debt to bridge the difference between their deposit and the purchase price. That is not always the correct way to view a £5m-plus facility.

A wealthy buyer may hold £20m or £30m of liquid and investment assets and still prefer not to put £12m into one property. The decision could be driven by liquidity, business commitments, estate planning, investment exposure, currency or the simple desire not to concentrate too much wealth in an illiquid home.

Karis interprets the increase as evidence that more wealthy buyers are using debt to preserve capital for other investments. That is an industry interpretation rather than a conclusion established by the FCA data itself. The numbers prove that a meaningful regulated large-mortgage market exists; they do not reveal the motivation of every borrower.

For each client, the reason should be made explicit. Borrowing merely because investments might outperform the mortgage is not a plan unless the comparison includes tax, fees, volatility, security and the possibility that returns disappoint while interest remains payable.

The £12m London House: Cash, Mortgage or a Blend?

Consider a client buying a £12m London residence with £25m of liquid investments and further business assets. Paying cash would complete the acquisition without debt and remove interest-rate risk. It would also move almost half the liquid portfolio into one property before stamp duty, legal costs and ongoing ownership expenses.

A £7m property mortgage would leave more capital invested or available. The client would incur interest and fees, provide a charge over the house and need to satisfy affordability and source-of-wealth checks. Depending on the lender, the facility could be fixed, floating, repayment or interest-only.

A private bank might assess the entire balance sheet and accept income that is awkward for a standard mortgage model. It may also request or require investment assets under management. The client should calculate the combined cost of borrowing, custody and investment management rather than treating a lower loan margin as the complete price.

A securities-backed facility could provide some or all of the deposit without selling investments or taking a charge over the property. That introduces a different risk: if collateral values fall or eligibility changes, the lender can require more assets or repayment.

A blended structure might use a property mortgage for the long-term core and a smaller portfolio-backed line for timing or flexibility. More components do not automatically create a better result; each adds documentation, cost and possible interaction between assets.

Conventional Large Loans Can Be More Relevant Than Expected

Not every £5m-plus mortgage needs a private bank. Certain mainstream and specialist lenders have large-loan teams, defined maximums and underwriting models that can assess high income, professional earnings, bonuses, retained profit or investment income.

A property-led mortgage can be attractive where the client wants to keep investments with the existing wealth manager. The lender takes security over the property rather than using the portfolio as collateral, although wider assets may still support the affordability narrative or repayment strategy.

The limitations can include maximum LTV, loan size, property appetite, income evidence, term and acceptable repayment vehicles. A trophy residence, unusual construction, large acreage or substantial ancillary accommodation may require more specialist valuation and underwriting.

The comparison should begin across the market. Moving immediately to the client’s existing private bank can be efficient, but it may leave other credible property-lending routes untested.

Private Banking: Price the Whole Relationship

Private banks can be particularly useful where income is international, irregular or secondary to the client’s asset position. They may structure interest-only debt, consider several currencies, take additional security or align repayment with a future liquidity event.

The quoted mortgage margin can depend on assets under management. A bank may offer attractive property-debt pricing because it expects a substantial investment relationship. That is not necessarily poor value, but the transfer should be assessed on its own merits.

Compare investment-management fees, custody, deposit requirements, FX costs, credit margin, arrangement fees and the consequences of removing assets later. If moving £10m of investments saves a modest amount on the mortgage but increases ongoing portfolio costs, the apparent lending advantage can disappear.

Concentration also matters. Holding investments, cash and property debt with one institution can simplify administration, yet it can reduce negotiating leverage and make a future change more disruptive.

Lombard Lending Solves a Different Problem

Lombard lending or securities-backed lending uses eligible investments as collateral. It can provide liquidity without selling the portfolio, potentially avoiding an ill-timed disposal and allowing the property to be acquired without or alongside a mortgage.

Availability depends on what the client owns. Cash, government bonds and diversified liquid securities may attract different advance rates from concentrated equities, private funds or illiquid investments. Some assets may be ineligible.

The facility is normally dynamic. If markets fall, the collateral value and lending headroom can fall too. The client may have to add assets, repay debt or accept a sale. A £5m property mortgage does not ordinarily create that daily market-linked collateral risk.

The correct comparison is therefore not simply mortgage rate versus Lombard rate. It is property security and longer-term underwriting versus portfolio security and mark-to-market exposure.

Interest-Only Does Not Remove the Repayment Question

Interest-only borrowing can be appropriate for clients with substantial assets and a clear repayment plan. It preserves cash flow and avoids forced capital repayment during the term.

The lender may accept investment assets, a future property sale, business proceeds, trust distributions or another defined source as the repayment strategy. The existence of wealth is not enough; the bank will want to understand ownership, accessibility, currency, liquidity and timing.

The client should test the plan independently of optimistic asset growth. If repayment depends on selling the home, the likely future housing requirement matters. If it depends on investments, the wealth adviser should consider whether the portfolio can realistically support the liability without compromising the wider plan.

Buying for Cash and Refinancing Later

Cash can strengthen a buyer’s negotiating position and remove mortgage timing from the purchase. Some clients therefore complete with cash and arrange debt afterwards.

A post-purchase refinance can release capital trapped in the property, but it should not be assumed. The lender will assess the property value, ownership, source of purchase funds, reason for capital raising and the borrower’s wider position. Some lenders apply minimum ownership periods or different criteria to recently acquired property.

The amount released may be lower than expected if the valuation, LTV or affordability does not support the target. Tax and legal consequences of the ownership and borrowing structure should be considered by the client’s advisers before the cash purchase, not reconstructed after completion.

If future refinancing is important, an indicative debt review before exchange can establish whether the intended exit from cash is credible.

International Buyers Add Currency and Jurisdiction

Mortgage Introducer reports continued interest from buyers connected to the UAE, Hong Kong and Singapore. International clients can present strong balance sheets but require lenders able to understand foreign income, businesses, trusts, investment accounts and source of wealth.

Currency creates an additional decision. Borrowing in sterling against a UK property can avoid a currency mismatch on the asset, but repayments may be funded from foreign income or investments. Borrowing in another currency can appear cheaper while exposing the client to exchange-rate movements.

Residence, nationality, tax location and ownership structure influence the lender market. A British expatriate, UAE national and Hong Kong entrepreneur purchasing the same property may receive different options because their income, jurisdictions and banking relationships differ.

Specialist advice should map the client before approaching lenders. A large deposit alone does not resolve jurisdiction, verification or affordability questions.

The London Concentration Is Striking—but Not Surprising

With 292 of the 333 reported mortgages secured in London, the £5m-plus regulated market remains overwhelmingly tied to the capital. London has the property values, international buyer base and private-banking infrastructure to generate loans of this size.

The data should not be read as proof that London’s super-prime market is broadly booming. The same Mortgage Introducer report points to softer prime prices and lower top-end transaction activity. Higher large-loan volumes can coexist with weaker prices if more purchasers choose debt or if the composition of transactions changes.

For buyers, softer conditions can create negotiation opportunities. Funding readiness still matters: a client able to evidence cash, secure credit approval and choose between several funding routes may negotiate more confidently than one who has not established how completion will be financed.

What Wealth Managers and Family Offices Should Ask

The first question is not “which bank offers the lowest mortgage rate?” It is “what does the client want to preserve?” That may be investment exposure, cash reserves, ownership flexibility, the existing wealth relationship or the ability to repay without penalty.

The adviser should establish whether a portfolio disposal would affect tax, asset allocation or long-term returns. The debt specialist should show which facilities require assets under management, which use property security alone and how each route behaves if markets or rates move adversely.

Willow’s recent review of UK wealth-management assets and organic growth explains why solving a client’s borrowing requirement without automatically exporting the investment relationship has become a meaningful professional capability.

Seven Questions for a £5m+ Debt Review

How Willow Private Finance Can Help

Willow provides large and complex property-finance advice for UK and international clients, including cases where substantial assets exist but the correct debt structure is not obvious.

We can compare conventional large loans, specialist HNW lenders, private banks, international banks, property-backed lending and portfolio-backed routes where relevant. The analysis covers total cost, required asset transfer, collateral, liquidity, interest and repayment structure, concentration and exit flexibility.

For wealth managers, family offices, lawyers and tax advisers, we can discuss the funding requirement before the client liquidates assets or accepts one bank’s default structure. Each professional remains responsible for advice within their own remit.