Mark Leyden & Associates Data Breach Exposes Sensitive Financial Client Information
Mark Leyden & Associates, a wealth management and financial advisory firm based in Indianapolis, Indiana, recently disclosed a data breach involving unauthorized access to an employee email account. The incident, which occurred between May and October 2025, was detected and contained, but a subsequent investigation revealed that sensitive client data had been compromised.
On February 18, 2026, the firm confirmed that exposed information included names, Social Security numbers, driver’s license numbers, and financial account details. The breach was reported to state authorities on March 24, 2026, with affected individuals notified via written letters. At least six individuals across Maine, Massachusetts, and New Hampshire were impacted.
The firm, founded in 2007 and affiliated with the national advisor network Lion Street, specializes in financial strategies for high-net-worth clients and businesses. Legal representatives are now investigating potential compensation claims for those affected.
Source: https://www.claimdepot.com/investigations/mark-leyden-associates-data-breach-2026
Lion Street cybersecurity rating report: https://www.rankiteo.com/company/lion-street
"id": "LIO1774537349",
"linkid": "lion-street",
"type": "Breach",
"date": "5/2025",
"severity": "60",
"impact": "2",
"explanation": "Attack limited on finance or reputation"{'affected_entities': [{'customers_affected': 'At least six individuals across '
'Maine, Massachusetts, and New '
'Hampshire',
'industry': 'Financial Services',
'location': 'Indianapolis, Indiana, USA',
'name': 'Mark Leyden & Associates',
'type': 'Wealth management and financial advisory '
'firm'}],
'attack_vector': 'Unauthorized access to employee email account',
'customer_advisories': 'Written letters to affected individuals',
'data_breach': {'number_of_records_exposed': 'At least six individuals',
'personally_identifiable_information': 'Yes',
'sensitivity_of_data': 'High',
'type_of_data_compromised': ['Names',
'Social Security numbers',
'Driver’s license numbers',
'Financial account details']},
'date_detected': '2025-10',
'date_publicly_disclosed': '2026-02-18',
'description': 'Mark Leyden & Associates, a wealth management and financial '
'advisory firm, disclosed a data breach involving unauthorized '
'access to an employee email account. The incident exposed '
'sensitive client data, including names, Social Security '
'numbers, driver’s license numbers, and financial account '
'details.',
'impact': {'data_compromised': 'Sensitive client data, including names, '
'Social Security numbers, driver’s license '
'numbers, and financial account details',
'identity_theft_risk': 'High',
'legal_liabilities': 'Potential compensation claims',
'payment_information_risk': 'High',
'systems_affected': 'Employee email account'},
'investigation_status': 'Ongoing',
'references': [{'source': 'Incident disclosure'}],
'regulatory_compliance': {'legal_actions': 'Potential compensation claims',
'regulatory_notifications': 'Reported to state '
'authorities on March '
'24, 2026'},
'response': {'communication_strategy': 'Written letters to affected '
'individuals',
'containment_measures': 'Incident was detected and contained'},
'title': 'Mark Leyden & Associates Data Breach Exposes Sensitive Financial '
'Client Information',
'type': 'Data Breach'}