FEDERALItem 1.05 · mandatoryHackingHealthcareHealthcareSupply Chain (3P Vendor)Business Associate (HIPAA)Customer Data InvolvedDownstream VictimsDelayed DiscoveryPHIPIIHealth (basic)Identity (basic)LowActive

The Oncology Institute, Inc.

bd_383278f2de77324b · schema v1 · pii pii-v1

Severity

Low

Discovered

May 20, 2026

Filed

May 22, 2026

To disclose

2 days

Affected

Not disclosed

Confidence

81%

Full breach record for The Oncology Institute, Inc. →2 incidents on file

The Oncology Institute, Inc. filed an Item 1.05 8-K supplementing its November 6, 2025 voluntary 7.01 disclosure regarding a cybersecurity incident at a software service provider (Vendor). On May 20, 2026, Kroll, the Vendor's third-party administrator, notified the Company that an unauthorized third party had accessed certain Company information systems, including systems containing patient data. The Company states operations continued in all material respects and it will work with the Vendor to offer credit monitoring to impacted patients.

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SEC clockMateriality determined May 20, 2026 → Filed May 22, 20262d ✓ SEC 4-day OK2 days discovery → filing

⚠ unattributedNo provenance was recorded for this discovery date and it matches no other date on the record. It may be correct, but it is not independently grounded.

Incident timeline

discovery → filing · 2 days

May 20, 2026

Discovered

May 22, 2026

Filed

vs. sector median

11 wks faster

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

Name: The Oncology Institute, Inc.
norm: the oncology institute
SEC CIK: 0001799191

Name: The Oncology Institute, Inc.
norm: the oncology institute
SEC CIK: 0001799191
Industry: Healthcarellm

Discovered: May 20, 2026
Materiality determined: May 20, 2026
Notification sent: —
Affected individuals: Not disclosed
Data types: PHIPIIHealth (basic)Identity (basic)
Attack vector: Third-Party / Supply Chain
MITRE ATT&CK: T1195 Supply Chain Compromise
Threat actor: External
Initial access: supply_chain

During the incident: Worked swiftly in response pursuant to the Company's technology security and continuity plan
Will work with the Vendor to offer credit monitoring and protection to all impacted patients
Reserving all rights with respect to potential claims against relevant third parties or service providers
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 2 days(2 days from discovery to filing)
Compliance flags: SEC 4-day OK · 2d
Discovery-date grounding: unattributedNo provenance was recorded for this discovery date and it matches no other date on the record. It may be correct, but it is not independently grounded.
Clock breakdown: Statute Window Elapsed Threshold Status
SEC
Materiality determined: May 20, 2026
→ Filed: May 22, 2026
2d cal. 4 business days SEC 4-day OK

Statute	Window	Elapsed	Threshold	Status
SEC	Materiality determined: May 20, 2026 → Filed: May 22, 2026	2d cal.	4 business days	SEC 4-day OK

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 filing

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

SEC 8-K / victim statementThis record

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

Source URL: https://www.sec.gov/Archives/edgar/data/1799191/000107997326000721/toi_8k.htm
DisclosureLens renders the full SEC/HHS filing inline below from the originating regulator’s public record (§4.5 fair report privilege).
Filed at: May 22, 2026
Raw hash: 283426e44d27f447a868a528c6272add59ec8003e4a30992b631ddbe308875be

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Reporting entityThe Oncology Institute, Inc.

Victim entityThe Oncology Institute, Inc.

Incidentdiscovered May 20, 2026

Stated responseWorked swiftly in response pursuant to the Company's technology security and continuity plan

ComplianceSEC 4-day OK

Extraction provenanceno artifact recorded

Source provenancewww.sec.gov

Source filing