"Bank–level" security means we adhere to the same security encryption standards as your bank. We routinely run security audits to ensure we meet these standards at all times. On top of internal audits, VeriSign — one of the internet's leading online security firms — validates our security.
We also physically protect the servers we store your information on. To access our servers, you would first have to bypass round–the–clock guards, then bypass doors with electronic lock systems. The servers themselves are locked behind protective cases and are monitored 24/7 by surveillance cameras. If someone were able to get past all that security and break into a server, they would then have to crack several layers of authentication and military grade 256-bit encryption to access any data.
(It sort of sounds like a James Bond movie, doesn't it?)