Apple's 7 Billion Dollar Man

Just how much is Steve Jobs worth? The announcement that he was taking another medical leave has prompted considerable speculation about the future of Apple. The value of most CEOs is probably marginal, but Jobs has led Apple from triumph to triumph at a stunning pace.

We can use the stock market to measure Jobs's worth to the company. Apple's stock fell 2.25 percent on Tuesday, which translates to a drop in market capitalization of $7.2 billion in one day. Not to worry, Apple is still valued at more than $312 billion. And as the New York Times reports, Apple has plenty of managerial talent, including ground breaking engineers, marketing managers and industrial designers.

Financial analysis provide a more precise measure called abnormal return that compares the movement of a particular stock price to the market as a whole. The difference can be used to estimate the effect a particular news event has on a stock price. The S&P 500 was up 0.14 percent Tuesday, which would put Jobs's market valuation at $7.6 billion. If we use the NASDAQ index (up 0.38 percent Tuesday) as a benchmark, Jobs' market valuation would be $8.4 billion.

But Tuesday's loss could be made up quickly following Apple's announcement of a truly astonishing quarter announced after the market closed. The company posted revenue gains of $7.8 billion (70 percent) compared to the same quarter last year, which translated into increased net income of $6 billion, a 78 percent increase. Earnings per share climbed to $6.43, more than a dollar higher than analysts' expectations. Has such a large company ever displayed such stunning growth?