High-value individual subject matter experts and technical contributors need feedback in order to improve their performance. The Expertship360™ is the world's #1 tool for helping experts understand where they are performing, and where they could perform better. Expertship is a relatively new word aligned with but quite different to leadership. Expertship is defined as the insightful application of expertise leading to optimal outcomes (Gordon & Johnson, Master Expert, Expertunity Press 2021). Expertship describes what tech, financial, engineering, scientific, legal, actuarial, manufacturing, project managers and other experts – often the unsung heroes - do to keep the lights on in your organisation, and very often they find innovative ways to do so more effectively. Experts want to know how well they are doing compared to other experts, but need a valid assessment tool that makes sense in the complex environments in which they work. The Expertship 360™ allows experts to gain feedback from immediate and removed stakeholders, and measures the effectiveness of experts benchmarked against the Expertship model, The tool identifies areas of strength and development to work on, and delivers unparalleled actionable insights into performance and the opportunities where experts can add more value.