UK banks Lloyds TSB, the Co-operative Bank and Halixfax IT systems' went down briefly on Friday, causing problems for some users.
"There has been a system issue, all our systems are now back up and running," a spokeswoman for Lloyds TSB told ZDNet at 3:41pm BST on Friday.
On Twitter, people had reported having problems accessing their account balance, using online banking and withdrawing money.
One Lloyds customer told ZDNet they had been unable to access online banking at 2:45pm and when they rang the bank at 3pm they were told "our systems are completely down".
Based on the reports published on Twitter, it seems problems began in the mid-afternoon and were mostly fixed by around 3:15pm on Friday.
The three banks have millions of customers between them, with the Co-operative Bank claiming 2.4 million retail customers.
Earlier in the year RBS, another major UK banking group, had a prolonged week-long outage due to failures in its IT systems. The system meltdown hit NatWest, RBS and Ulster Bank Customers and the bank was forced to put aside £125m to cover costs and compensation.