Incident · State breach notice (California AG)
Mercadien CPAs Notifies Clients After Unauthorized Access to Files Containing Social Security Numbers
Published 2026-10-14. By the cisonews.net Desk.
What the notice says
Mercadien, P.C. CPAs notified affected individuals, including residents whose information it handled through client engagements, after discovering that an unauthorized party had accessed files on its network. Mercadien states the files involved included names and Social Security numbers tied to an advisory services engagement. According to the notice as filed, . The notice explains that Mercadien , followed by a review to determine whose data was present.
Mercadien states that the affected files came from a separate source tied to its advisory work, noting that . The notice also clarifies that . Mercadien is offering recipients complimentary Experian IdentityWorks credit monitoring and identity restoration services, along with a dedicated engagement number for verification purposes.
What the notice leaves open
The notice as filed does not provide an overall total number of individuals affected nationwide, stating only that . It does not describe how the unauthorized access occurred or specify a start date for the unauthorized activity beyond the detection date. The notice does not name the financial institution client associated with the exposed files.
Sources
- 2026-10-12 · AMercadien, P.C. CPAs, notice filed with the California Attorney General, published October 12, 2026
- 2026-10-12 · ACalifornia Attorney General, data breach notification record, published October 12, 2026
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