In the latest example of massive identity exposure, the University of California at Berkeley admitted Monday that a thief swiped a laptop containing nearly 100,000 names and Social Security numbers of students, prospective students, and alumni.

The disappearance March 11 of an unwatched laptop from the Graduate Division offices of the university was reported Monday under a California law that requires consumers be informed when their data has been compromised. UC Berkeley had postponed the warning in the hopes that campus police would recover the portable.

The purloined PC contained files with the names of more than 98,000 people, including those who applied to its graduate school between fall 2001 and spring 2004, grad students who enrolled at Berkeley between fall 1999 and fall 2003, and recipients of doctorates from 1976 through 1999.

Although the UC system requires that all sensitive data on laptops be encrypted, the files on the stolen notebook had not been encoded; according to a campus spokesperson, they were scheduled for encryption the afternoon the PC was stolen.

The university is trying to reach the 98,369 people via snail mail and e-mail, but as a precaution, suggested that they consider putting a fraud alert on their credit reporting accounts.

At the same time, it tried to put a good face on the event. "The campus has no evidence that personal data were actually retrieved or misused," the school said in a statement.

The campus has created a web site with more information, and is manning toll-free lines that people can call to find out if their data was on the missing machine.

This isn't the first data loss to strike Berkeley. Last fall, state officials revealed that a hacker broke into a university computer containing a database with the names and Social Security numbers of some 1.4 million Californians.

Other California schools have been struck, too. Last week, Chico State announced that hackers had made off with information on 59,000 people from its network, and almost a year ago, hackers broke into the computer system of the University of California, San Diego, compromising confidential information on about 380,000 students, teachers, employees, alumni, and applicants.