Fron what I know, at this moment the forms of attack targetting banks or financial institutes are dominantly via trojan horses and DDoS. Several incidents show that the trojans are frequently used when the criminals want to obtain bank-related information as much as possible. The news below shows that the attackers want the victim cannot run their financial business properly, even the DDoS attack could be a cover for hiding or disguising any online bank frauds. I hope the bank's security team has already taken some hardening actions to anticipate these attacks.
From The SANS Institute:
Attacks on US Financial Institutions Continue (March 29 & 30, 2013) A group claiming responsibility for a recent distributed denial-of-service (DDoS) attack against the American Express website is the same one that has been targeting US financial institutions since September 2012. While the primary focus of the group's efforts appears to be crippling the banks' websites, there is concern that the attacks could provide a cover for fraudulent transactions. http://arstechnica.com/security/2013/03/funded-hacktivism-or-cyber-terrorists-amex-attackers-have-big-bankroll/http://www.usatoday.com/story/tech/2013/03/29/american-express-denial-of-service-hack/2030197/