Health Plan of San Mateo

Health Plan of San Mateo notified California AG on Mar 17, 2023 of a data breach, which occurred on Jan 17, 2023. Data exposed: Social Security number, Financial / bank account, Health insurance, Date of birth, Email address, Name.

Case file (dates, days to notice against the statute, what the letter offers, prior incidents)

Organization: Health Plan of San Mateo
Source: California AG · source record
Date reported: Mar 17, 2023
Date(s) of breach: Tuesday, January 17, 2023
Residents affected: Not published by this source
Data exposed: Social Security number Financial / bank account Health insurance Date of birth Email address Name
Notice letter: Sample notice (PDF)
Discovered: Jan 17, 2023, as stated in the letter
"On January 17, 2023, we became aware of unauthorized access within our employee email environment."
Days to notice: 59 days from discovery (Jan 17, 2023) to the California record (Mar 17, 2023). Statute: 30 days from discovery or notification of the breach (Cal. Civ. Code § 1798.82). Over the statutory period
First seen by BreachTally: 2026-10-30 16:00 UTC

Dates and counts as filed by the organization with the agency. The breach window and the report date often differ by months.

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Data reproduced from a public government filing. Spot an error? Email support@breachtally.com with the record link. Corrections are applied and noted.