Wettermark Keith LLC Data Breach Investigation

Recently, Wettermark Keith reported to the Attorney General of New Hampshire that it had experienced a data breach in which sensitive personal identifiable information and protected health information in its care may have been compromised. According to the breach notice, on April 14, 2025, Wettermark Keith experienced a cyber incident involving unauthorized access to portions of its internal computer system.¹ As a result, Wettermark Keith launched an investigation to determine the nature of the incident.

Through its investigation, Wettermark Keith confirmed that sensitive personal information in its systems may have been accessed by an unauthorized third party during the breach. As a result, Wettermark Keith began a review of the data to determine what information had been impacted as well as identify the specific individuals affected. On September 15, 2025, Wettermark Keith completed this review. While the information impacted varies depending on the individual, the type of information potentially exposed includes:

• Name
• Social Security number
• Driver’s license number
• State identification number
• Financial account number
• Individual health insurance policy number
• Medical condition or treatment information

On October 1, 2025, Wettermark Keith began mailing data breach notification letters to impacted individuals. Based on the breach notice sent to New Hampshire residents, Wettermark Keith is providing affected individuals with a list of the specific types of sensitive information impacted and 12 months of complimentary credit monitoring services. A link to the breach notification letters that Wettermark Keith filed with the Attorney General of New Hampshire is below.