NEW YORK (CNN/Money) - Shares of Sun Microsystems surged Friday on vague takeover rumors, but some industry analysts discounted the likelihood the maker of computer and Internet gear would be bought out.

A spokesman for Sun, based in Santa Clara, Calif., said the company does not comment on market speculation.

Sun (SUNW: up $0.41 to $3.75, Research, Estimates) stock soared 12.3 percent Friday and was the most active Nasdaq issue by far. More than 130 million shares traded, nearly triple the average daily volume of 46.2 million shares.

Todd Salamone, director of research for Schaeffer's Investment Research in Cincinnati, which specializes in tracking options, said that there was stronger-than-usual activity in Sun's call options Friday. Increasing volume of call options is often viewed as a sign of a takeover; a call gives an investor the right to buy shares at a certain price at a future date.

Still, Robert Cihra, an analyst with Fulcrum Global Partners, said he did not think that a takeover was likely. Cihra, who follows hardware companies for Fulcrum, which does not do any investment banking, said that it wouldn't make much sense for competitors like Dell, IBM or Hewlett-Packard to buy Sun.

Another analyst, who asked not to be named, dismissed the rumors as mere speculation.

Dell (DELL: up $0.39 to $29.57, Research, Estimates), in particular, has eschewed acquisitions. HP (HPQ: up $0.15 to $16.65, Research, Estimates) is about to celebrate its one-year anniversary of its merger with Compaq. And IBM (IBM: up $1.68 to $87.57, Research, Estimates) has been trying to bulk up in businesses outside of hardware, with recent purchases of Rational Software and the consulting arm of PricewaterhouseCoopers.

All three stocks were trading higher on Friday as well, which seems to indicate that the market doesn't expect any of these companies to make a deal for Sun.

In addition, Sun Chairman and CEO Scott McNealy exercised options to sell 1.6 million shares last week.

Sun may be seen as a takeover target because it has been hit harder than most techs during the past few years as companies have cut back on purchases of its proprietary servers. The stock is trading nearly 95 percent below its all-time high, set in the summer of 2000. Servers are computers that link other machines in corporate networks.

And the company is facing increased competition from companies making servers based on Microsoft's Windows, as well as from servers running on the open source Linux operating system.

It is for this precise reason that Sun is not a good strategic fit for other hardware companies. There are serious questions about whether or not Sun will be a long-term survivor in the server marketplace.

"I can't think of anyone who would want to buy Sun," said Michael Cohen, director of research for PacificAmerican Securities, which does no investment banking. "Nobody is going to spend more than $10 billion for a company that might go away on its own." Sun's current stock market value is about $12 billion, including Friday's gains.

If anything, Cohen said, Sun would be wise to try and acquire a company that could help boost its competitive position. Despite its troubles, Sun does have a strong balance sheet, with $5.5 billion in cash and just $1.5 billion in long-term debt.

Sun posted a small profit in its fiscal third quarter last month but sales were lower than expected. For the fourth quarter, which ends in June, analysts are expecting Sun to earn 2 cents a share, up from a penny a year earlier. Sun is expected to post revenue of $3.1 billion, a 10 percent decline from a year ago.