Key insight: Regional bank CEOs on Friday sought to ease the concerns of investors who've grown jittery about banks' credit quality after the disclosure of certain issues related to allegedly fraudulent loans.What's at stake: One bank CEO said the recent credit problems are "uncorrelated events."Supporting data: The KBW Nasdaq Regional Banking Index stabilized on Friday after falling some 7% at times during the prior day.Amid market turmoil that roiled bank stocks this week, regional bank CEOs are trying to ...