Interest-Only Mortgages: Risks, Rules and Exit Strategies

An interest-only mortgage means your monthly payments cover only the interest on the loan — not the capital itself. At the end of the mortgage term, the full original loan amount is still outstanding and must be repaid in one lump sum.

How Interest-Only Mortgages Work

On a repayment mortgage, each payment reduces the outstanding balance. On interest-only, it does not. After 25 years of interest-only payments on a £200,000 mortgage, you still owe £200,000.

Monthly payment comparison:

The £360/month saving sounds attractive — but at the end of 25 years, the repayment borrower owns their home outright while the interest-only borrower owes £200,000 and must find the money to repay it.

Who Can Get an Interest-Only Mortgage?

Since the FCA’s Mortgage Market Review (2014), lenders apply strict criteria:

• Repayment vehicle: You must demonstrate a credible plan to repay the capital. Acceptable vehicles include an ISA or investment portfolio, sale of the property (for downsizers), other property equity, pension lump sum, or endowment policy.
• Minimum equity: Most lenders require 25–50% equity (LTV of 50–75%).
• Minimum income: Many lenders have income floors of £75,000–£150,000 for interest-only lending.
• Minimum loan size: Some lenders only offer interest-only above £300,000.

Interest-only is now primarily a product for higher-equity, higher-income borrowers, not a route to reduce monthly payments for first-time buyers.

The Maturity Risk

The biggest risk with interest-only is reaching the end of the term without an adequate repayment plan. This became a crisis for many borrowers in the 2010s who had taken out interest-only mortgages in the 1990s–2000s with endowment policies that underperformed.

If you cannot repay the capital at the end of the term:

• The lender can apply for possession of the property
• You may be forced to sell
• If the property value has fallen, you could face a shortfall

Lender Communication

Responsible lenders are required to contact interest-only borrowers as their term approaches to check whether they have a repayment plan in place. Do not ignore these communications.

Exit Strategies

Switch to repayment: Convert your mortgage to repayment at any time, either at a product switch or remortgage. Your monthly payments will rise but the loan reduces each month.

Part-and-part: Split your mortgage so part is on interest-only and part on repayment. A compromise that reduces the capital at risk while keeping payments manageable.

Overpayments: Make voluntary overpayments (up to your lender’s allowance, typically 10% of balance per year) to reduce the outstanding capital.

Downsizing: If your plan is to sell and downsize at the end of the term, this is a valid repayment vehicle — but requires that the property value has not fallen and that there is sufficient equity to clear the mortgage and fund the next purchase.

Remortgage to a longer term: Some borrowers extend the term when approaching maturity. This can only work if you are still within the lender’s maximum age limits (most lenders cap at age 70–75).

Interest-Only for Buy-to-Let

Interest-only is far more common in buy-to-let than residential mortgages. Landlords often choose interest-only to maximise cashflow (rent minus interest), intending to repay capital from property sale proceeds. The same end-of-term risk applies, though rental properties are typically sold to fund repayment rather than being the borrower’s home.

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