MUFG Union Bank, N.A.

MUFG Union Bank, N.A. notified California AG on Dec 11, 2018 of a data breach, which occurred on Nov 22, 2018. Data exposed: Financial / bank account, Usernames / passwords, Name.

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

Organization: MUFG Union Bank, N.A.
Source: California AG · source record
Date reported: Dec 11, 2018
Date(s) of breach: Friday, November 9, 2018Thursday, November 22, 2018
Residents affected: Not published by this source
Data exposed: Financial / bank account Usernames / passwords Name
Notice letter: Sample notice (PDF)
Discovered: November 2018, as stated in the letter
"MUFG Union Bank, N.A. (“MUB”) recently determined that an unauthorized third party may have used your login credentials to gain access to your Union Bank Online and/or Mobile Banking account in November 2018."
Days to notice: 19 days from the end of the breach window (Nov 22, 2018, no discovery date in the letter) to the California record (Dec 11, 2018). Statute: 30 days from discovery or notification of the breach (Cal. Civ. Code § 1798.82).
Offered in the letter: credit or identity monitoring through Experian
Third party: The letter attributes the incident to a vendor or service provider
First seen by BreachTally: 2026-10-30 16:14 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.