LONDON, September 26 — Plum, the UK money management app, has raised the interest rate on its Cash ISA to a market-leading 5% AER, but the offer lasts only five days and comes with a catch that savers should read carefully. The limited-time deal, launched on 25 September 2026, applies to new customers who open an account between 25 and 30 September 2026. The 5% rate is variable and includes a 2.46% AER bonus for the first 12 months.
After that first year, the bonus drops away and the underlying rate — whatever it is by then — takes over.
What Plum is offering
Victor Trokoudes, Plum’s CEO and founder, said the offer is designed to encourage saving as summer spending ends and the festive season approaches. He noted the 5% rate is “far higher than both the Bank of England’s base rate and the inflation rate,” ensuring customer money grows in real terms and is protected from tax. The mechanics are simple enough.
The Cash ISA is a tax-free savings account available to UK residents aged 18 or over. Interest is paid monthly, and the minimum opening deposit is £1 (about US$1.35).
The account is available only through Plum’s mobile app. Adam French, head of consumer finance at Moneyfactscompare.co.uk, described the rate as “comfortably market-leading” but warned savers must act fast because it is only available to new customers via the app between 25 and 30 September 2026. French also noted the rate is variable, so the underlying rate is subject to change.
The catch
Plum is not a bank. The company says it uses bank-grade protection for personal information and holds customer money with authorised banks. That distinction matters for anyone weighing where to park their savings.
The offer arrives as UK savers face a landscape where the Bank of England base rate and the inflation rate are both lower than 5%, making the deal attractive for those seeking real returns. Plum’s move follows a broader trend of fintech apps competing for deposits by offering promotional rates.
The five-day window creates urgency. New customers who miss the 30 September deadline will not get the 5% rate, and those who do sign up will see the bonus expire after 12 months. What to watch next is whether other providers respond with competing offers, and whether Plum extends or repeats the promotion once the window closes.
