According to the New York Times, Southeastern Asset Management, a private equity firm, now owns 21 percent of Sun Microsystems, up from 16.5 percent in August. Southeastern is putting pressure on Sun's management to, as they say, "maximize the value of the company." Sun's been losing revenues and market share for a long time, but it's still profitable. At the time of this writing, the amount of cash that Sun has on hand (nearly $3.5 billion) exceeds its market capitalization ($3.26 billion.) Some of that cash could be used for a stock buyback, which would raise the stock price, or for acquisitions that would have the potential of reigniting Sun's growth. It's clear that Sun, as currently constituted, is a cash cow whose best days are well behind it. Sun's management can't remain in a holding pattern; its investors won't let them.