On Tuesday, January 9th, the U.S. stock markets closed mixed, influenced by a slight uptick in Treasury yields, leading to the S&P 500 and Dow Jones ending the session in the red. In economic data, the NFIB Small Business Optimism Index climbed to 91.9 in December from 90.6 in November. The US trade deficit decreased to $63.2 billion in November, better than the expected $65 billion gap. Most of the 11 key S&P sectors experienced declines, with energy seeing the largest drop; the tech sector was among the four sectors that gained. The Dow Jones Industrial Average decreased 0.42%, closing at 37…