The new fixed bonus rate offer, which came into effect on June 8, applies for 12 months to savings accounts or cash ISAs. The Marcus savings account and cash ISA both currently have an interest rate of 1.05 percent, meaning the rate will increase to 1.3 percent with the bonus.
Current customers must activate the bonus themself online or via the app.
Users can set up the bonus via their account at any time and it will be applied for 12 months from the date that it is started.
Newcomers opening an account with the group will get the bonus automatically and there is no need to apply.
An individual must be a UK resident and aged 18 or over to set up an account, and will need to provide an email address, phone number and National Insurance number.
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An account can be set up and managed online, and customers can give some instructions over the phone.
Funds can be transferred from a linked account, which must be a UK current account in the customer’s name.
A person can set up an account with just a £1 deposit.
The money should show in the Marcus account as soon as it has been received and will start earning interest on the same day.
The cash ISA is not a flexible ISA, so any withdrawals cannot be replaced and will still count towards an individual’s annual ISA allowance.
Any tax-free benefits on the amount taken out will also be lost, meaning a person may have to pay tax future interest they earn on that amount.
Interest is calculated daily and paid monthly accounts, and the rate is variable.
Customers will be informed of any reduction in the rate at least 14 days before the new rate comes in and any increases will be communicated as soon as possible after it begins.
Customers will need to pay in £1,000 to set up the account.
Rachel Springall, finance expert at Moneyfacts.co.uk, said: “The deal pays 2.55 percent gross and may well appeal to savers who are comfortable with locking away their cash to secure a competitive return over the shorter-term.
“Overall, this account receives an Excellent Moneyfacts product rating.”
The maximum amount they can earn this interest on is £85,000.
Moneyfacts also singled out Coventry Building Society for its Easy Access ISA online account, for those who need instant access to their savings.