More power now lies in chief executive McNealy's hands

Sun said it will not be seeking a replacement. Instead, his duties will be absorbed by chief executive, Scott McNealy, who will also reassume the title of president.

Investors were rattled by the departure of Mr Zander, who is the fourth executive to leave the firm in just a few weeks.

Sun shares closed nearly 15% lower at $6.79.

Restructuring and cutbacks by big customers meant Sun made a 14 cent a share loss in the three months to December 2001, although the company insisted it will return to the black in the current April-June quarter.

One after the other...

But neither that, nor Mr McNealy's insistence during a conference call that the departures are simply delayed from last year because of the turmoil in the tech markets, is calming investors.

"I know it looks like a flurry here," Mr McNealy said. "I think it's been positive and planned out.

"We are on plan in executing just about everything we wanted to do here from a management succession and organisation structure perspective."

The other departures - chief financial officer Mike Lehman, head of computer systems John Shoemaker and head of services Larry Hambly - were less problematic in the view of some analysts.

"Recent management changes don't bother us, though Mr Zander's leaving would," Merrill Lynch analyst Steven Milutinovich told clients in a note transmitted on 30 April, the day before the resignation was announced.