Amazon became the most valuable publicly traded company in the U.S. for the first time on Monday (January 7th), passing Microsoft during an ongoing volatile time for the stock market. Amazon’s shares rose three percent yesterday to close at $1,629.51 and lift its market value to $797 billion. Microsoft’s stock moved up by less than one percent, leaving its value at $784 billion. Microsoft had briefly returned to the top spot after passing Apple in late November. Amazon’s market value has been higher, standing at more than $1 trillion in September. However, Apple’s market value had been even higher at the time, before losing about $400 billion in value since then.