The Trustees are the governing body of the IISS with responsibility for the financial and general management of the Institute. They serve in a dual capacity: as Directors for the purposes of the Companies Act, and as Trustees for the purposes of the Charities Act.

Trustees meet formally at quarterly meetings in London but maintain regular contact with the Institute’s directors throughout the year, acting in an advisory capacity on major projects and participating in the Institute’s events. There are two Trustee sub-committees: the Investment Committee meets quarterly to monitor the investment of reserves and determine investment policy, the Audit Committee meets annually to evaluate financial control and risk mitigation systems.

The Trustees appoint members of the IISS Council, the Institute’s intellectual advisory body.

IISS Governance and Advisory Structure