New York Community Bancorp's stock decline raises concerns about broader banking crisis. The bank's expansion to over $100 billion in assets after acquiring Signature Bank has led to unexpected losses on real estate loans, causing its stock to plummet by half. This has also affected other lenders with commercial real estate portfolios. The bank's reluctance to address future profit expectations has intensified worries, leading to a 40% drop in its stock value. (Characters: 498)