Enough said:

Right away, one ought to notice the staggering growth rate in both revenue and earnings that Apple displayed in 2008. Apple’s real revenue grew 54.5% from $24.637 billion in FYE 2007 to $38.041 billion in FYE 2008 — a full $13.4 billion growth in revenues. Even more impressive is Apple’s 81.2% growth rate in adjusted net income. For a company that is trading at 12 times 2008 earnings, it doesn’t take a genius to conclude that Apple is severely undervalued. Especially since Apple currently trades at about 3.37 times its cash position — which is objectively and significantly lower than every other large cap tech company.

GOOG trades at 7.18 times its cash position, RIMM at 15.51 times cash, AMZN at 9.15 times cash, MSFT at 9.13 times cash, CSCO at 3.62 times cash, IBM at 10.96 times cash, INTC at 6.54 times cash, and HPQ at 5.15 times cash. What is more, only GOOG, AAPL and MSFT have no debt of the companies mentioned above. Apple has the largest net cash position than any of those companies and Apple has more net cash than RIMM, GOOG, AMZN and IBM combined.

Via Daring Fireball. That could explain today's gains.