Stratton D. Sclavos, CEO and board member of digital infrastructure vendor VeriSign, resigned from the company Tuesday. No reason was given for the resignation.

In a statement Tuesday, Mountain View, California-based VeriSign gave no reason for Sclavos' resignation but said he will be replaced as CEO by William A. Roper Jr., who will also be named president. Roper, who has been a VeriSign director since November 2003, will become a full-time employee of VeriSign, according to the company. Roper formerly was an executive vice president at Science Applications International Corp., where he also was chief financial officer from 1990 to 2000.

Also announced was the election of Edward A. Mueller as board chairman.

Sclavos' departure after 12 years of leading the company comes after a nearly yearlong internal review into VeriSign's stock options practices by the company's board. That review, which is almost complete, "did not find intentional wrongdoing by any current member of senior management, including Sclavos," the company said.

Last June, VeriSign received a grand jury subpoena from the U.S. attorney for the Northern District of California requesting documents related to VeriSign's stock option grants and practices, as well as an informal inquiry from the U.S. Securities and Exchange Commission requesting similar documents.

In November 2006, the company said it would "restate its historical financial statements for the years and interim periods from 2001-2005 and for the first quarter of 2006 to record additional non-cash, stock-based compensation expense related to past stock option grants."

The company confirmed "it has identified certain grants with incorrect measurement dates, without required documentation, or with initial grant dates and prices that were subsequently modified."

VeriSign indicated that the restatements could cost the company about $US250 million.

Sclavos, who previously was president and board chairman of the company , was one of VeriSign's first employees in July 1995, according to the company. He received a wide range of awards and honors in the technology world, including from Computerworld (U.S.), Morgan Stanley, Ernst and Young, and Forbes magazine.

A VeriSign spokesman was not immediately available for comment.

"VeriSign is a highly respected company with an attractive business model and leading positions in growing markets," Roper said Tuesday in a statement. "The board remains committed to our strategy, and is pleased with the early results of the restructuring program we began this year. I look forward to working with VeriSign's management team to capitalize on the company's growth opportunities while ensuring the strongest possible emphasis on managerial discipline and execution."

Mueller, the new chairman, joined VeriSign's board in March 2005 and is the former CEO of Williams-Sonoma, a specialty retailer, according to VeriSign. In 1968, he joined the former SBC Communications and was chief executive of several business units.

"We thank Stratton Sclavos for all he has accomplished for VeriSign," Mueller said in a statement. "Over the last 12 years, he helped establish VeriSign as a global corporation that millions of consumers and businesses rely upon every day as they interact on the world's voice and data networks. We wish him continued success in the future."

In a statement, Sclavos thanked VeriSign employees for their work during his tenure. "I am proud of my role in building VeriSign into the great company it has become, and wish all of my associates the very best in the coming years," he said.