Savings Interest Rates, Switch Offers and Guides for Castle Trust Bank

Who they are

Castle Trust Bank launched in October 2012, initially backed by US private equity firm J.C. Flowers & Co., and started out offering investment products and specialist mortgage finance. In 2018 the firm was invited to pursue a banking licence, and by June 2020 it became a fully authorised bank. Today it sits in a slightly unusual space: its range covers savings and Cash ISA accounts alongside specialist bridging and term mortgages, and retail finance.

As at September 2025, around 36,000 customers held just under £1.5 billion of fixed term, fixed rate and notice account savings with the bank. It is not a household name, but it has been quietly building a solid savings book for several years. Managing your accounts is handled through an online portal and mobile app.

Savings accounts

The only product currently listed on DepositScout for Castle Trust Bank is the Notice e-Saver - a 120-day notice account paying 4.20% AER (variable) with a minimum balance of £1,000. Notice accounts were added to the savings range in May 2024. There are no introductory bonuses or teaser rates attached, which means the rate you see is the rate you get - at least until the bank decides to change it, as it is variable.

The 120-day notice period is the key thing to weigh up here. You need to submit a withdrawal request and then wait four months before the money arrives. That is a meaningful restriction, so it suits savers who know they will not need quick access to the funds.

Eligible deposits with Castle Trust Bank are protected up to £120,000 by the Financial Services Compensation Scheme (FSCS) - any deposits above that limit are unlikely to be covered. The bank holds its own licence, so this protection is not shared with another brand.

Is it right for you?

Castle Trust Bank is worth considering if you want a clean, no-fuss notice account with a competitive rate and no bonus cliff to worry about. The 4.20% AER sits towards the top of the notice account market, though it is worth knowing that easy access accounts from other providers can match or beat this figure with no waiting period at all - so the trade-off is real.

There are no switch offers available at the moment, and the product range on DepositScout is narrow, so if you want a broader relationship - fixed-rate bonds or a Cash ISA under the same roof - you may want to explore those directly with the bank.

As always, rates move. Check the live figures shown on this page before you apply.