Unless understand your comment wrong: most older EU banks run their core on mainframe. Sure the webapp to see your account is running on some websphere/j2ee or nowadays maybe even angular server. But that's just a gateway to the real accounting system on the mainframe.
Brazilian banks and parts of the government were pretty big mainframe clients. I’m most familiar with the IBM ones, but Unisys also had quite a footprint with their A series (which evolved into the Clearpath Libra family).
