Tenet /ˈtɛnɪt/: a belief or principle that is held to be true by members of a group or organisation.

Our name

Tenet Advisory was founded by Lindsay O’Sullivan who has decades of experience helping organisations transform, grow and respond to the changing needs of stakeholders in complex environments across a range of industries. He has held C-Suite and non-executive roles in complex, regulated entities and has worked with boards, regulators, funders, and governments on issues that demand clarity, collaboration and strong judgment. His work spans strategy execution, growth, organisational culture and performance, governance, technology adoption, financial management, risk management, stakeholder management, capability uplift, customer experience, innovation, and digital transformation.

Lindsay is known for building trust quickly, creating alignment across leadership teams, simplifying complex environments, and empowering people so they can act with confidence.

This lived experience informs how Tenet partners with leaders and why our approach focuses on what works in the real world rather than consulting theory.