Apple Becomes Biggest Stock of All Time

Apple entered the record books Monday, becoming the most valuable stock to have ever traded.

Apple closed at another historic high of $665.15 on Monday, ending the day with a record market cap of $623.5 billion. With the gain, Apple (AAPL) eclipsed Microsoft's (MSFT) peak market cap of $618.9 billion, a level that Microsoft hit more than 12 1/2 years ago, on Dec. 30, 1999. That happened at the height of the dot-com boom and just three months before the Nasdaq Composite peaked at its all-time high of 5,132.52.

Nothing seems to be slowing down Apple's stock these days. Shares have been on the rise over the past three months in high anticipation of new iPhone and iPad models that have been predicted to hit stores during the second half of this year. Even a disappointing earnings report late last month did little to spook investors as they remained focused on the widely expected, but not yet formally announced.

In fact, Apple has seen its market cap double from $300 billion to $600 billion in a mere 19 months. Now, Apple's colossal market cap is roughly equivalent to the combined market caps of tech titans IBM (IBM), Google (GOOG), Intel (INTC), and Hewlett-Packard (HPQ).

As Apple's stock continues to push higher, the gap between its market cap and that of the second largest company, Exxon Mobil (XOM), continues to widen.