Eisner Advisory Group Data Breach Affects 84,795 Americans

On March 25, 2025, Eisner Advisory Group LLC discovered a significant data breach affecting the personal and sensitive information of thousands of individuals. The breach occurred on two separate dates: September 4, 2023, and September 9, 2023. During these incidents, unauthorized actors gained access to confidential consumer information stored within the company's systems.

The breach exposed personally identifiable information (PII) including names, addresses, Social Security numbers, driver's license numbers or other state-issued identification numbers, passport numbers, dates of birth, financial account information, and payment card information. Additionally, protected health information (PHI) such as medical information and health insurance details were also compromised.

In total, the breach impacted 84,795 individuals across the United States. Specifically, 82 residents of Maine, 249 residents of Montana, and 130 residents of New Hampshire were affected.

Currently, Eisner Advisory Group LLC has not publicly identified the exact method used by the unauthorized actors to access their systems or the identity of the responsible parties. The company has reported the incident to multiple state attorney general offices, including the California Attorney General's Office, Maine Attorney General's Office, Montana Attorney General's Office, and New Hampshire Attorney General's Office.

Eisner Advisory Group LLC submitted official disclosures to each state's attorney general, which can be viewed online. For more detailed information, please refer to the data breach disclosures on the websites of the California Attorney General's Office, Maine Attorney General's Office, Montana Attorney General's Office, and New Hampshire Attorney General's Office.

Eisner Advisory Group's response

In response to this data breach, Eisner Advisory Group LLC notified affected consumers directly by written notices on April 8, 2025. The company has also provided a dedicated webpage containing further information about the breach, available on the EisnerAmper website.

Given the severity of the breach and the sensitive nature of the information exposed, Eisner Advisory Group LLC recommends that affected individuals take immediate steps to protect their personal and financial information. These steps include closely monitoring financial accounts and credit reports for any suspicious activity, promptly reporting any unauthorized transactions to financial institutions, and considering placing a fraud alert or security freeze on credit files to prevent potential identity theft.

About Eisner Advisory Group LLC

Eisner Advisory Group LLC operates as part of the EisnerAmper brand, offering comprehensive business advisory and non-attest services. It is one of the largest business consulting firms in the United States, employing more than 2,000 professionals and 200 partners nationwide. Eisner Advisory Group LLC forms an alternative practice structure alongside EisnerAmper LLP, which provides attest services. This structure complies with the AICPA Code of Professional Conduct and relevant laws, ensuring high ethical and professional standards.

The firm specializes in advisory services, including risk and compliance, strategy and transformation, financial advisory, and settlement administration. Additionally, Eisner Advisory Group LLC provides tax planning, compliance, and consulting services tailored to businesses, governmental entities, nonprofits, and high-net-worth individuals.

Eisner Advisory Group LLC is part of the global EisnerAmper network, which maintains offices in international locations such as the Cayman Islands, Singapore, and Ireland. In fiscal year 2022, EisnerAmper reported net revenues of $614 million, reflecting its strong presence and extensive client base across diverse industries.