Nahhh - some banks have some parts of the infrastructure in COBOL. Specifically larger retail banks often have their ledgers in COBOL. Most of them want rid and are actively getting rid. Most places have had programs to root COBOL out since before 2000, but there are residual implementations remain. The ledgers are the hardest place to deal with because of the business case as well as the awkwardness. Basically there's not much of an advantage (or at least hasn't been) in modernizing so keeping the thing going has been the option. Now people want to have more flexible core systems so that they can offer more products, although not so sure that customers want this or can consume it. Still - it supports the idea of modernisation so not many people are keen to challenge.

The most common big implementations I come across are in Java.