The Shared Surface

The median institution shares AI dependencies with 300 other institutions.

85,491
Pairwise links via dominant vendor
8.3×
Larger than the next vendor group
99%
Cross-institutional surface concentrated in top three vendors

When two regulated institutions both deploy AI agents through the same vendor, they share a dependency surface. A governance event at the vendor reaches both institutions at the same time. Across the v13.1.0 substrate, 414 of 543 institutions sit on the dominant vendor ecosystem. The pairwise dependency surface this generates is 85,491 links, an order of magnitude larger than the next vendor group. DORA Article 28 governs each pair bilaterally. The aggregate surface is the concentration risk that ESA designation under DORA Articles 31 to 44 was created to address. The substrate quantifies it at the agent level, where supervisors can act.

Figure 1 · Pairwise Cross-Institutional Links by Vendor Group
0 20k 40k 60k 80k Hyperscaler A 85,491 links · n=414 Hyperscaler C 10,296 links · n=144 Hyperscaler B 9,870 links · n=141 Foundation Model B 2,346 links · n=69 Enterprise Vendor A 1,378 links · n=53 PAIRWISE CROSS-INSTITUTIONAL LINKS Bilateral regulation. Multilateral exposure. MAR®500.com

Each bar measures the count of pairwise institutional links generated by shared dependency on the named vendor group. A pairwise link exists between two institutions when both deploy at least one agent through the vendor. The pairwise count is the upper bound of cross-institutional propagation through that vendor: a governance event at the vendor reaches every institution dependent on it simultaneously. Hyperscaler A generates 85,491 links, larger than all other vendor groups combined. The link count is independent of agent count and measures the structural dependency surface, not the operational footprint.

Source · Meridian substrate v13.1.0, May 2026 · Pairwise links computed as n(n-1)/2 over distinct institutions sharing each vendor Methodology · SSRN 6535599
Cite this finding
Collins, B. (2026). The Shared Vendor Surface in Regulated Financial Services. Meridian Autonomy substrate v13.1.0, sealed 29 April 2026, SHA256 e5250de8e9de07d6. Retrieved from https://mar500.com/shared-surface
Substrate · v13.1.0 Sealed · 29 April 2026 SHA256 · e5250de8e9de07d6 Domain · Systemic Governance Risk
543 institutions · 12 sectors · 95,876 agents · 636,854 governance edges · substrate v13.1.0
Methodology grounded in Systemic Governance Risk in AI Agent Networks, SSRN Working Paper 6535599. Substrate methodology in The Stationary Sea (Part 1: Substrate Construction) on Zenodo.