Banking Sector Volatility: First Republic Troubles Deepen While Other Regional Banks Rally.

First Republic Bank's credit rating was cut again by Standard & Poor's, causing a 19% premarket drop. UBS shares fell 5% and Credit Suisse shares plunged 58% after UBS announced it would buy Credit Suisse for $3.2 billion. New York Community Bancorp jumped 25% after Flagstar Bank took over large parts of Signature Bank's deposits and loan portfolios. Enphase Energy added 1% after Raymond James upgraded it to outperform. US Bancorp gained more than 4% in early trading.