At Oakstead Finance, we work with NatWest regularly and have a practical understanding of how the lender approaches applications. NatWest’s porting rules are unusually specific about what counts as “like-for-like” — borrowing the same or less, a term the same or longer, the same repayment type and the same applicants — and stepping outside any of those triggers different pricing on the extra funds.
What Does NatWest Porting Actually Involve?
Porting with NatWest means moving an existing rate onto a new property rather than starting a fresh mortgage from scratch. The existing mortgage must be redeemed on completion, though the old property does not need to be sold to a third party — it can be repaid from savings or refinanced with another lender.
- ✪ A first mortgage payment must have been made before the port can proceed.
- ✪ Some Right to Buy, Green and shared equity products are not portable as standard.
- ✪ There is no minimum balance requirement — a balance under £25,000 can still be ported.
- ✪ Two properties can be sold and their rates ported into a single new purchase, under the same brand.
How Much Can Be Borrowed When Porting a NatWest Mortgage?
The amount available depends on whether the application stays like-for-like or asks for more. Like-for-like means the borrowing is the same or less, the term is the same or longer, the repayment type is unchanged and the applicants are unchanged — that combination keeps the ported rate intact with no early repayment charge.
- ✪ Additional borrowing of £10,000 or more is priced on a New Business Rate.
- ✪ Additional borrowing of £9,999 or less defaults to NatWest’s Standard Variable Rate.
- ✪ The LTV attached to the original ported rate does not carry over — a borrower on a 70% LTV product can move to a 90% LTV purchase, with any extra funds priced on the new LTV band.
How Does NatWest Treat Income When Porting?
Porting is reassessed against current affordability rules rather than the figures used on the original application, so income evidence effectively starts again. Employed applicants need six months of continuous employment, treated as unbroken where any gap between roles is under three weeks, while self-employed applicants need two full years of trading history.
A change in income, employment status or credit profile since the original mortgage was taken out can affect what is available on the port, even where the property and loan amount stay identical. Standard residential eligibility also applies throughout — applicants must be between 18 and 75, and NatWest does not lend on properties for applicants who are not UK resident at the point of application.
What Is the Underwriting Process Like for a NatWest Port?
A port is underwritten as a fresh application in most respects, with a hard credit search, income verification and a valuation on the new property. Where the case is a like-for-like port with a declined agreement in principle, brokers are directed to contact NatWest’s business development team directly rather than resubmitting blind.
Turnaround varies with case complexity, documentation and whether additional borrowing is involved, so a specific timescale should always be checked against the current position at application rather than assumed. Since remortgage timescales can move with market volume, building in a buffer around a moving date is normally sensible.
What Happens if More Borrowing Is Needed on a NatWest Port?
Where a buyer is moving to a more expensive property, NatWest allows a top-up alongside the ported amount, assessed on current income, outgoings and credit standing rather than the figures behind the original loan.
- ✪ A minimum loan size of £25,000 applies for the broker’s procuration fee to be paid on the full amount.
- ✪ Customers who have taken Cost of Living Support with a temporary switch to interest-only in the last six months cannot apply for additional borrowing during that period.
- ✪ Additional borrowing runs as a separate illustration alongside the ported product, not blended into a single rate.
NatWest at a Glance
| Criteria | NatWest Position |
|---|---|
| Minimum balance to port | None — balances under £25,000 can still port |
| Additional borrowing threshold | £10,000+ on New Business Rate; under that, SVR |
| Employed income evidence | 6 months continuous employment |
| Self-employed income evidence | 2 full years trading |
| Age range | 18 to 75 |
| Non-portable products | Some Right to Buy, Green and shared equity deals |
A Worked Example of Porting With NatWest
Consider a hypothetical Fulham couple with an existing NatWest mortgage of £340,000 at 70% LTV on their current £485,000 flat. They agree a sale and want to buy a £560,000 house with a £60,000 deposit uplift, meaning £400,000 is needed against a property that puts them at roughly 71% LTV overall. Because the new borrowing of £400,000 exceeds their existing £340,000 balance, the extra £60,000 is additional borrowing rather than a like-for-like port. As it is over £10,000, that portion is priced on a current New Business Rate rather than the couple’s existing rate, while the original £340,000 continues on the ported terms, subject to the new property’s LTV band and a fresh affordability check on both applicants’ current income.
NatWest Compared With Other Porting Options
Halifax offers a broadly similar like-for-like porting structure to NatWest, but assesses additional borrowing through its own affordability model, which can produce a different maximum where income is mixed between salary and bonus. Skipton Building Society, used more often through brokers than on the high street, tends to take a more flexible view of complex or recently-changed income on a port, which can suit applicants whose earnings picture has shifted since their original NatWest application.
What You Need to Know About NatWest Porting
- ✪ Porting a NatWest mortgage keeps the existing rate but resets the underwriting — income, credit and property value are all re-checked.
- ✪ Staying like-for-like avoids an early repayment charge; borrowing more triggers New Business Rate or SVR pricing on the extra funds.
- ✪ A first payment must have been made on the existing mortgage before a port can go ahead.
- ✪ Some products, including certain Right to Buy and Green deals, are not portable as standard.
For a fuller view of how a port compares with starting fresh, Oakstead Finance’s product transfer guide sets out the trade-offs between switching rate and moving lender entirely.
Frequently Asked Questions
Can a NatWest mortgage always be ported?
Most NatWest mortgages are portable, but certain Right to Buy, Green and shared equity products are excluded as standard. The mortgage offer document is the most reliable way to confirm whether a specific product is portable.
Does porting a NatWest mortgage avoid the early repayment charge?
A like-for-like port — same or lower borrowing, same or longer term, same repayment type and same applicants — avoids the early repayment charge. Reducing the balance being ported can trigger a partial charge on the amount not carried over.
How much can be borrowed when porting with NatWest?
The ported amount follows the existing balance, while any additional funds are assessed against current income and the new property’s loan-to-value. Additional borrowing of £10,000 or more is priced on a New Business Rate rather than the ported rate.
What income evidence does NatWest need for a port?
Employed applicants need six months of continuous employment, and self-employed applicants need two full years of trading history. This applies even where the applicants and property type have not materially changed since the original mortgage.
Can two properties be sold and combined into one NatWest port?
Yes, where both properties are under the same NatWest mortgage, the rates on each can be ported into a single new purchase, subject to the usual affordability and product rules.
Is there a minimum loan size to port with NatWest?
There is no minimum balance to port, though a minimum loan size of £25,000 applies for a broker’s procuration fee to be paid on the full application amount.
How long does a NatWest port take to complete?
Timescales depend on case complexity, documentation and whether additional borrowing is involved, so a current estimate should always be checked at application rather than assumed from a general figure.
What happens if additional borrowing is needed on a NatWest port?
Additional borrowing runs as a separate application alongside the port, assessed on current income and outgoings, and is not available to customers within six months of taking Cost of Living Support involving a temporary interest-only switch.
