After my meeting with General Electric Co. (NYSE: GE) CFO Keith Sherin last week, I tried to figure out how much GE's NBC Universal might be worth in the open market. Such analysis is relevant now for two reasons:

• GE's stock price has fallen 2% under its current CEO. When Jeff Immelt took over as CEO on September 7, 2001, GE was trading, 2%, or 87 cents, above today's $38.79. During that same period, the S&P 500 rose 40%. In predecessor Jack Welch's first 5.9 years as CEO, GE's stock rose 221% from a split-adjusted $1.40 in April 1981 to $4.50 in March 1987.
• A respected analyst recently advocated a breakup to get GE stock moving. The New York Times [registration required] recently reported that Citigroup Inc.'s (NYSE: C) John Sprague issued a report titled "Partial Break-Up Could Break Deadlock on the Stock."

Is GE worth more broken up in pieces and sold or kept intact? To answer this, let me explain how a conglomerate like GE can raise its stock price. My theory is that GE management has two levers: the P/Es of the industries in which GE competes and the earnings growth rates of its businesses in those industries. To increase GE's market value, its management should prune GE's portfolio of businesses with the lowest P/Es and slow earnings growth -- replacing them with high P/E, fast earnings growth businesses which it can run successfully (if that can be done without overpaying). Nevertheless, as noted here, I am not sure whether a conglomerate is a good corporate strategy for GE because it may be leading the stock market to discount its earnings by 4%.

I address whether breaking up GE will increase its stock price in Breaking Down GE, a seven-post series.