Apple briefly surpassed ExxonMobil on Tuesday to become the largest US company in terms of market value. The market capitalization of both Apple and ExxonMobil was more than $340 billion with the California gadget-maker edging past the oil giant at around 1:20 pm before falling back, Meeschaert analyst Gregory Volokhine said.Apple dethroned software giant Microsoft in May of last year to become the largest US technology company in terms of market cap -- the number of shares outstanding multiplied by the stock price.Apple shares were up 3.50 percent at $365.58 in mid-afternoon trading on Wall Street.ExxonMobil shares were down 1.33 percent at $69.26. Apple stock has risen steadily over the past few years as chief executive Steve Jobs piloted the release of a string of hit products starting with the iPod in 2001, followed by the iPhone in 2007 and the iPad last year.