"Market Plunge: Stocks Drop, Dow Falls 300 Points, Futures Decline"

US stocks fell at the start of the four-day trading week, with the Dow Jones, S&P 500, and Nasdaq all declining. Goldman Sachs reported a fourth quarter earnings jump, while Morgan Stanley's shares dipped after a quarterly profit impacted by a one-time charge. Federal Reserve Governor Christopher Waller believes the Fed will be able to lower interest rates this year, but cautioned that the timing and rate cuts will depend on incoming data. Additionally, a proposed merger between JetBlue and Spirit Airlines was blocked by a federal judge, and the Nasdaq turned positive as Nvidia stock gained.