Savers can earn hundreds of extra pounds per year in interest without switching banks, according to the analyst Savings Champion.
Experts said these so-called hidden deals at Britain’s biggest high street banks could generate almost £1,000 more in interest annually, without the hassle of changing to a new provider.
Lloyds customers with £50,000 in cash savings can earn an extra £875 a year by moving from the Easy Saver, which pays 0.5pc, to the Club Lloyds Advantage Saver at 2.25pc.
However, Anna Bowes of Savings Champion warned “there can be catches to watch out for”. While the Easy Saver offers unlimited withdrawals, she said, returns on the Club Lloyds Advantage Saver will drop to 0.3pc if more than three withdrawals are made a year.
Savers also need to be Club Lloyds members, which means paying £3 a month for a current account. The fee is waived each month that at least £1,500 is paid into the account; this will rise to £2,000 from April.
Savers at other banks can also earn significant sums for switching accounts.
At Barclays, savers with £50,000 can earn an extra £760 by moving the funds from the Everyday Saver at 0.5pc to the Blue Rewards Saver at 2.02pc.
The Rainy Day Saver is another option, which pays 5.12pc on deposits of up to £5,000. Savers who move £5,000 from the Everyday Saver to the Rainy Day Saver can earn an extra £231 a year.
Customers also have to be Blue Rewards customers, which involves paying £5 a month for a current account. The fee is returned if two direct debits are paid out of the account. Returns on the Blue Rewards Saver drop to 0.5pc in months that withdrawals are made.
Savers at HSBC can make an extra £535 by moving £50,000 from the Flexible Saver at 0.65pc to the Online Bonus Saver, which pays 3pc on the first £10,000 deposited and 1.4pc after that.
However, returns on the Online Bonus Saver drop to 0.65pc in any month if a withdrawal is made. The account can only be opened online, whereas the Flexible Saver can also be opened in a branch.
Santander savers can earn an extra £475 if they move £50,000 from the Everyday Saver, which pays 0.55pc, to the eSaver (Issue 21) at 1.5pc. The eSaver can only be managed online or if it is linked to an existing Santander cash card.
Ms Bowes said: “You can probably earn more if you shop around and move your cash to the top rates, but don’t forget to check whether your bank can help you to squeeze a little extra from your savings.”
With some options only available online, Ms Bowes added: “Older people who prefer branch banking may not be able to make use of these top paying accounts.”
Barclays, HSBC and Lloyds each said they offered a range of accounts for different circumstances, such as regular savers and those accounts for lump sum deposits. Santander did not respond to a request for comment.