Apple is most valuable company of all time

The stock reached a record high of $664.74 a share, which translates into a market value of $623.13 billion. No other American company has ever reached such lofty heights. Shares have fallen to $661 in the last hour or so, but the record market value will stand if the stock closes at $657.50. The WSJ notes that Apple's market cap is more than $200 billion greater than Exxon Mobil. A big reason for the run-up is the expected release of new iPhone and iPad products. From the Journal:

Apple's sway on major benchmark indexes has been well documented for much of the year. But the latest figures from [Howard Silverblatt, senior index analyst at S&P Dow Jones Indices], underscore just how important Apple's rally is for the rest of the market. The S&P 500′s tech sector is up 16% since October when the broad market hit its all-time peak, he says. But stripping away Apple from the calculation and the sector is down 3.7% throughout that same time frame.

Chart: CNNMoney