The Hidden Network: Board Interlocks Across the FTSE 100

The Web That Connects Corporate Britain

When a director sits on the boards of two companies simultaneously, they create a direct information channel between those organisations. Multiply this across hundreds of directors and dozens of companies, and you get a dense network of interlocking relationships.

Our analysis of 30 major FTSE 100 companies reveals over 74,000 board-level connections — a web far denser than most observers assume.

The Super-Connectors

Some individuals sit at the nexus of this network. The most connected FTSE 100 directors typically share three characteristics:

• They are non-executive directors — executive directors rarely have time for multiple board mandates
• They have long careers across multiple companies — each board seat adds connections
• They serve on large boards — a director at a company with 15 board members has more co-directors than one at a company with 8

Cross-Sector Bridges

The most governance-relevant interlocks are those that cross sector boundaries. When a banking director also sits on a mining company's board, they bring financial sector governance norms into a different industry context.

Our data shows that the financial services → industrial bridge is the most common cross-sector interlock pattern in the FTSE 100. Insurance companies, with their investment-driven perspective, are particularly well-represented on non-financial boards.

The Governance Question

Board interlocks aren't inherently problematic. The UK Corporate Governance Code focuses on time commitment rather than connection count. But research suggests that highly interlocked boards can exhibit conformity bias — converging on similar governance practices not because they're optimal, but because they spread through the network.

Explore any executive's connections on their profile page, or find the shortest path between two executives using our Path Finder.