Recent economic data and earnings reports have bolstered the confidence of JPMorgan's trading team, leading them to believe that US stocks will experience a rebound by year-end. The team, led by US Market Intelligence Head Andrew Tyler, notes that the data indicates that the US economy remains in an expansionary state, with positive growth in corporate earnings, and the Federal Reserve is considering easing monetary policy. Although the upside potential has weakened compared to previous predictions, the team still believes there is substantial upward potential. They predict that the S&P 500 index will set a new historical high this year, followed by strong performance in the fourth quarter.