Leading U.S. banks like Goldman Sachs, JPMorgan, Morgan Stanley, and Bank of America flagged sharp revenue growth from their prime brokerage arms in Q3. Surging hedge fund activity, elevated valuations, and leveraged strategies fueled demand for credit, securities lending, and financing services. Some banks cautioned, however, that this boom may not be sustainable given rising concerns about overextended markets and tightening margin requirements. The rally in prime services underscores how banks are monetizing volatility and capital-market depth to boost earnings.