The personal information of 98,191 Minnesotans may have been released in a large data security breach at Nationwide Mutual Insurance Co. earlier this fall, state insurance regulators said Monday.

Altogether, 1.1 million people were affected by the attack on the company's network, but the insurer said Monday that it has no evidence that the personal information the hacker or hackers obtained had been misused. The FBI is investigating the data breach, which was discovered and addressed on Oct. 3.

The breach involved customers of Columbus, Ohio-based Nationwide Mutual and its affiliate Allied Insurance, as well as people who had requested insurance quotes online. The company, among the largest insurers in the country, said the information potentially released included names and possibly Social Security numbers, driver's license numbers, birthdates, marital status, gender, occupations and the names and addresses of people's employers.

Nationwide Mutual began notifying people of the breach on Nov. 16 and has offered them free credit monitoring and an identity theft protection product for one year. Company spokeswoman Elizabeth Giannetti said Monday that most of the people affected should have their letters by now.

Because the FBI is investigating the attack, Giannetti said she couldn't reveal much, except that it involved a "sophisticated perpetrator" and a small portion of the company's computer network.

"I can confirm that it came from outside the United States," Giannetti said.

According to the Identity Theft Resource Center, a nonprofit group in San Diego that tracks data breaches, there have been more than 400 security breaches reported this year, roughly on par with 2011. A spokeswoman characterized the Nationwide Mutual breach as large.

If you think you have been affected by the breach or have questions about the free services being offered, call Nationwide's toll-free number at 1-800-760-1125.

Jennifer Bjorhus • 612-673-4683