The banquet for the US stock market is coming to an end? American economists warn: the three major upward drivers are weakening. Although the S&P 500 index has risen by 24.72% since the beginning of the year, the main driving force for the continued rise of the US stock market is almost exhausted, indicating that the future return on investment in the US stock market will significantly decrease - this is the view of renowned American economist David Rosenberg.