Alleghany Corporation

Alleghany Corporation is a holding company engaged in property and casualty reinsurance and insurance through its subsidiaries, with additional investments in non-financial businesses held via Alleghany Capital. Founded in 1929 by railroad entrepreneurs Oris and Mantis Van Sweringen, the company transitioned over decades from rail holdings into specialty insurance and reinsurance, and is headquartered at One Rockefeller Plaza in New York City. Its principal insurance subsidiaries are Transatlantic Reinsurance Company (TransRe), a global reinsurer founded in 1977 with roughly 600 employees across 23 offices and more than $40 billion in claims paid to date; RSUI Group, a wholesale excess and surplus (E&S) underwriter spanning Property, Casualty, Professional Liability, Management Liability, and Binding Authority lines; and CapSpecialty, a specialty casualty and surety underwriter. Alleghany Capital holds non-insurance operating companies including toy and collectibles maker Jazwares (Squishmallows, Pokémon, Roblox, Fortnite licensed lines). On March 21, 2022, Berkshire Hathaway announced an $11.6 billion all-cash acquisition of Alleghany at $848.02 per share, which closed in October 2022. Alleghany now operates as a wholly-owned subsidiary of Berkshire Hathaway, contributing approximately $8.8 billion in 2025 gross premiums written and roughly $14 billion in insurance float to the parent. As a holding company whose operating units distribute exclusively through reinsurance intermediaries, wholesale brokers, and independent agents, Alleghany and its subsidiaries do not publish a developer portal, OpenAPI specifications, SDKs, or any other machine-readable API artifacts; the only digital surfaces exposed publicly are gated broker and agent login portals.

Kin Score

This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.

How we profile Alleghany Corporation

Each block below is one kind of artifact we hold for Alleghany Corporation. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.

Security Posture 1

Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Alleghany Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Every other property we hold for Alleghany Corporation — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.

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