Hallisey & D'Agostino Data Breach Affects 16,683 People

Hallisey & D'Agostino, LLP, a full-service accounting firm based in Wethersfield, Connecticut, experienced a data breach that affected 16,683 individuals in the United States, including 981 in New Hampshire, 737 in Massachusets and 74 in Maine.

The breach was discovered on March 19, 2026. The breach was reported to the attorneys general offices of Maine, Massachusetts and New Hampshire. The company began notifying affected consumers in writing on April 17, 2026.

On Oct. 21, 2025, Hallisey & D'Agostino identified unusual activity in its computer network. The firm took steps to secure its network and launched an investigation with the support of external cybersecurity experts.

The investigation determined that an unknown actor gained unauthorized access to the firm's network over a period of roughly 24 days, between Sept. 28, 2025, and Oct. 22, 2025. During that time, the actor potentially acquired certain files from the firm's systems.

The personal information compromised as a result of the breach included names, Social Security numbers, driver's license numbers, financial account numbers such as credit/ debit numbers and access information.

Hallisey & D'Agostino's response

The firm is offering affected individuals complimentary identity theft protection services through IDX, a data breach and recovery services provider. The services include credit and CyberScan monitoring, a $1,000,000 insurance reimbursement policy and fully managed identity theft recovery services.

Affected individuals can enroll in the identity protection services by visiting the IDX enrollment page or by calling 1-888-201-9274. Each affected individual will receive a unique enrollment code in their written notification letter, which is required to complete the enrollment process. The deadline to enroll in these complimentary services is July 17, 2026.

Hallisey & D'Agostino has also set up a dedicated toll-free call center to assist individuals who have questions about the incident. The call center can be reached at 1-888-201-9274 and is available from 9 a.m. to 9 p.m. Eastern Time, Monday through Friday, excluding major U.S. holidays.