Current account providers' charges for slipping into an unarranged overdraft have fallen only slightly on average since the start of the year, according to analysis.
Despite criticism of the size of some fees charged, unarranged overdraft penalty fees have fallen by just £1.43 typically since the start of 2017, Moneyfacts.co.uk found.
In January 2017, the average unarranged overdraft fee, based on one penalty for a whole month, was £53.61, and today it stands at £52.18.
Rachel Springall, a finance expert at Moneyfacts, said: "Our statistics show that there has been very little change across the market and that there is still room for improvement."
She continued: "Thankfully, there are some main brands who have taken the opportunity to reduce the unarranged overdraft fee."
A previous investigation by Which? into unarranged overdraft fees found some can potentially cost more than a payday loan.
The Competition and Markets Authority (CMA) has said that in 2014, £1.2 billion of banks' revenues came from unarranged overdrafts.
Some banks have announced an overhaul of the way they charge for overdrafts.
For example, in July, Lloyds Banking Group, the UK's largest current account provider, unveiled plans for a simplified "pay-as-you-go" overdraft charging system, starting from November.
A spokeswoman for trade body UK Finance said the positive changes made to current accounts are expected to be reflected in data in the coming months.
She said: "Overdraft charges have fallen dramatically over the last year, with customers saving nearly £1 billion.
"Banks will continue to work with the regulator and the CMA to enhance clarity on fees and charges while implementing alerts and prompts to increase customers' awareness of their overdraft."