US regional bank stocks fall amid Wall Street concern over credit markets

1. Regional banks face scrutiny over bad and fraudulent loans. 2. Zions Bancorp reports $50 million charge-off, impacting its stock negatively. 3. Western Alliance is also dealing with a fraudulent borrower, impacting its shares. 4. First Brands' bankruptcy raises concerns about risky lending practices. 5. JP Morgan's CEO warns of potential systemic issues in banking.