MisuseFinancial ServicesFinanceData MishandlingCustomer Data InvolvedIdentity (basic)Government IDFinancial accountMediumResolved

Legg Mason & Co., LLC

bd_b699fed471219898 · schema v1 · pii pii-v1

Severity

Medium

Discovered

Sep 18, 2019

Filed

Nov 18, 2019

To disclose

9 weeks

Affected

1state residents only

Confidence

67%

Legg Mason & Co., LLC notified Montana residents of an inadvertent disclosure of personal information (names, addresses, SSNs, account numbers) by third-party transfer agent BNY Mellon on September 18, 2019. The data was provided to another financial institution serviced by BNY Mellon. No identity theft was reported. Credit monitoring services were offered.

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Incident timeline

discovery → filing · 9 weeks / 61 days

Sep 18, 2019

Discovered

Nov 18, 2019

Filed

vs. sector median

on median

Tracked as a single-filing incident — the only disclosure on record for this event so far.Confirmed1 affectedView incident

Name: Legg Mason & Co., LLC
norm: legg mason
Domain: leggmason.com

Name: Legg Mason & Co., LLC
norm: legg mason
Domain: leggmason.com
Industry: Financial Servicesllm

Discovered: Sep 18, 2019
Materiality determined: —
Notification sent: —
Affected individuals: 1state-resident count only
Data types: Identity (basic)Government IDFinancial account
Data elements: Social Security numberDate of birth
Attack vector: Third-Party / Supply Chain
MITRE ATT&CK: T1078 Valid AccountsT1119 Automated Collection
Threat actor: Partner
Third party: via BNY Mellon Investment Servicing (US) Inc.
Initial access: trusted_relationship

During the incident: BNY Mellon promptly took action to remediate the inadvertent access
An investigation was conducted
Legg Mason was notified
Offering 12-month membership in Experian’s ProtectMyID® Alert service at no cost
Changes made: Continually evaluate and modify practices to enhance security and privacy
Regularly oversee practices of service providers and review enhancements to their controls
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 9 weeks(61 days from discovery to filing)
Compliance flags: — (clock not assessable for this source)

Status: No extraction artifact recorded for this disclosure.

Evidence ladder

Leak-site claim

Attacker assertion only. Establishes: claim date, group, alleged victim.

Press / market report

Unlocks: incident narrative, operational impact. Still no compliance clock.

State AG / regulator filingThis record

Unlocks: discovery date, data types, affected count, compliance clock.

SEC 8-K / victim statement

Unlocks: materiality, stated response, full audit trail. Ceiling removed.

Source URL: https://dojmt.gov/wp-content/uploads/OCP/General-Notice-24.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Nov 18, 2019
Raw hash: 64fa328ec1f4d227252bc0fdf8192d92b280f00339628c60ce3277dd32bddb21

Reporting entityLegg Mason & Co., LLC

Victim entityLegg Mason & Co., LLC

Incidentdiscovered Sep 18, 2019

Stated responseBNY Mellon promptly took action to remediate the inadvertent access

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancedojmt.gov