North Castle Ventures

Sponsor / owner / steward

Sovereign Intelligence. Anchored in Armonk.

North Castle Ventures sponsors and stewards a focused Armonk portfolio, coordinating property ownership, operating partners, and the evidence required to turn physical assets into useful infrastructure.

Explore the property manager
Portfolio
355 / 357 Main Street
Campus
Armonk Professional Center
Operator
Sovereign Shells
357 Main Street at Armonk Professional Center
PORTFOLIO / 357 MAIN
355 Main Street at Armonk Professional Center
PORTFOLIO / 355 MAIN
Local compute hardware representing the property operating layer
OPERATING LAYER / SOVEREIGN

The Vatche Simonian master plan

Midcentury permanence outside. Frontier infrastructure within.

Anchoring the northern end of Armonk's walkable village center — neighbor to IBM World Headquarters, Swiss RE Americas, and Regeneron — the 36,007 SF campus projects institutional discretion while sovereign edge compute is woven invisibly into its core.

357 Main Street office interior with glass-and-steel architecture
357 MAIN / GROUND-UP

357 Main Street

A 22,000 SF glass-and-steel edifice with an integrated subterranean parking deck. Bedrock blasted from the site was salvaged to build the rear retaining walls, grounding the modern structure in the native geology. Purpose-built to host Class 2 SoC-integrated sovereign compute.

355 Main Street with its two-story glass lantern enclosure at the Armonk Professional Center
355 MAIN / THE LANTERN

355 Main Street

A 1960s-era brick building radically reimagined with a two-story glass enclosure and stone-clad elevator tower — the “lantern inside.” Oversized stone panels flow from the exterior into the lobby, concealing the mechanical core behind a monolithic, grounded atmosphere.

Operated independently by Native Agentic

Nate connects tenant diligence to operational proof.

Nate—the Native Agentic Technical Engineer—is the software operator for diagnostics, configuration, observability, updates, and orchestration. North Castle Ventures sponsors the ecosystem; Sovereign Shells manages the campus and property infrastructure.

Explore Nate at Native Agentic

For tenants

Diagnose, then activate.

Assess a candidate building or suite before commitment. Where compatible, bring tenant-owned silicon into an always-on private compute environment with dedicated IPs, subject to site and carrier review.

For landlords

Observe, prove, convert.

Document suite condition, scope infrastructure conversion, and evaluate managed address and telecommunications yield without implying dedicated physical occupancy.

A new asset class

Class A real estate, monetized as sovereign AI infrastructure.

The Armonk blueprint — architecturally significant properties, hardened base-building systems, and the Tripartite Ownership Model — is the empirical foundation of a dedicated fund targeting boutique campuses in strategic, high‑net‑worth enclaves.

Building the standard in the open — read the AI-Native Office RFC