| Porting a Mortgage — Key Facts | |
|---|---|
| What it is | Transferring your existing product rate and term to a new property |
| Not automatic | Requires lender approval — it is an application, not a right |
| New affordability check | Lender re-runs full affordability assessment on porting application |
| ERC risk | If porting fails or the window expires, Early Repayment Charges apply |
| Top-up rate | Additional borrowing on the ported balance is at current market rates |
| Timing gap | If sale completes before purchase, mortgage is redeemed — ERC can trigger |
Porting a mortgage means asking your lender to transfer your current product — rate, term and remaining balance — to a new property when you move. It is not a guaranteed right and requires a fresh application. It can save significant Early Repayment Charges if you are mid-fix and your existing rate is below current market rates.
When Porting Makes Financial Sense
| Scenario | Port or remortgage? | Reason |
|---|---|---|
| Your rate is below market (e.g. fixed at 2%; market is 4.5%) | Port | ERC less than rate saving over remaining fix |
| Your rate is above market | Pay ERC and remortgage | New rate saving exceeds ERC cost |
| ERC under 1% and fix ends within 6 months | Remortgage now | Small ERC; lock better rate |
| Borrowing significantly more | Port existing + top-up at market rate | Two-part mortgage |
| Downsizing | Port with partial repayment — check ERC on repaid portion | Some lenders charge ERC on excess repaid |
The Application Process
Porting requires a full new application. The lender will: re-assess your affordability against current income; commission a new property valuation; check the property meets lending criteria (construction type, tenure, location); and run a credit check. If your circumstances have changed materially since your original application (reduced income, new significant debt, credit issues) the porting application may be declined. (Source: FCA MCOB 11 — responsible lending)
The Critical Timing Gap Risk
The most dangerous scenario: your sale completes before your purchase. Between those two completion dates, your mortgage is redeemed from sale proceeds. Most lenders allow a porting window of 3-6 months to complete the purchase and reinstate the mortgage. If the purchase falls through or the window expires, the product is lost and current market rates apply. Halifax and Nationwide hold the rate in a porting facility for up to 6 months without charging ERC — confirm your lender's policy in writing before exchange.
| ⚠ Warning: If your sale and purchase do not complete simultaneously on the same day, you are in the timing gap. Confirm the porting window with your lender before exchange of contracts. |
Top-Up Borrowing — The Two-Part Mortgage
If you are buying a more expensive property and need to borrow more than your current balance, the additional amount is offered at your lender's current market rate — not your ported rate. You end up with two sub-accounts: the ported amount at your original rate and the top-up at current rate. When your fixed rate ends, the ported sub-account reverts to SVR unless you remortgage. Confirm with your lender whether sub-accounts can be combined at next product transfer.
Alternatives to Porting
| Option | Cost | Best for |
|---|---|---|
| Port existing mortgage | ERC waived; new valuation fee ~£200-£500 | Mid-fix; below-market rate; same lender |
| Pay ERC and remortgage | ERC (typically 1-5% of balance) + new arrangement fee | Rate saving exceeds ERC; or porting declined |
| Bridge loan | High interest (0.5-1.5%/month) + arrangement fee | Very short completion gap only |
| Let to buy | Consent to let fee; buy-to-let mortgage | Want to retain old property as investment |
| Disclaimer: This article is for information only and does not constitute financial, legal or tax advice. Figures correct at date of publication but subject to change. Always verify with primary sources (gov.uk, HMRC, FCA register) and consult a qualified adviser before making financial decisions. |
Frequently Asked Questions
Can I port to a cheaper property?
Yes — but you must repay the difference between your current balance and the new purchase price. Check whether your lender charges ERC on the repaid portion. Some lenders waive ERC on the excess as part of a genuine port; others do not. Get written confirmation before exchange.
My porting application was declined — do I pay ERC?
If porting is declined and you need to move, you must redeem the mortgage and pay the ERC. Some lenders waive ERC where decline was due to the property not meeting lending criteria (not your affordability) — escalate to the lender's complaints team or a mortgage broker if this applies.
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