Apple today became the most valuable public company of all time with combined value of its shares exceeding a previous record set by Microsoft. Shares closed up 2.6% to $665.15. The closing price of Apple pushed its market value to $623.52 billion, surpassing the $616.34 billion set by Microsoft on Dec. 27, 1999, according to S&P analyst Howard Silverblatt. Adjusted for inflation, however, Microsoft’s 1999 market value would be worth $850 billion in today’s dollars, the New York Times noted, but the Microsoft of August 2012 is worth $257 billion. With the market anticipating a new iPhone in September, Apple has gained more than 8% this month. In recent days speculation has heated up again over Apple’s possible entry into the TV business. Earlier speculation suggested the company was working on a TV set, but last week’s reports indicated the company was leaning toward a set-top box that would radically simplify the TV experience. Apple’s market capitalization is now $200 billion higher than Exxon Mobil, its top of the hill rival just over a year ago. Meanwhile, Facebook fell to a new low during the day of $18.75 before rebounding to close at $20.01.