Users of online banking services at Lloyds and Halifax reported problems with accessing their savings or using cashpoints on Thursday.
Customers claimed they were able to get into their accounts but they were incorrectly showing as empty on Thursday.
On Twitter, Halifax said it was aware of the issues and “working to have it back to normal soon”.
According to Down Detector, customers were experiencing issues with online banking, using a cashpoint, logging in, seeing their recent transactions and accessing their money.
Lloyds users in London appeared to be the most affected with at least 2,500 people reporting problems with the service.
Some 1,356 Halifax users also reported issues about 8am.
A Lloyds spokesman said at 11.15am the issues had been resolved.
He said: “Online banking is now back to normal. We’re sorry some of our customers had issues with it this morning.”
