Diplomacy was in the midst of a transformation from ‘old diplomacy’ to ‘new diplomacy’ one century ago, yet the changes were not welcomed by everyone. The renowned diplomat Harold Nicolson lamented the loss of the ‘stock market of diplomatic reputation’, meaning the corporate estimate of character built up during a lifetime of frontline diplomatic service. As we progress through another period of remarkable transformation in diplomacy, what has become of the stock market of diplomatic reputation? This article undertakes a case study of diplomatic alumni from a public policy training institute. It investigates understandings of the construct of reputation, concern for reputation and use of reputation. It finds that reputation remains very important to practising diplomats. Reputation is indeed a timeless feature that is intrinsic to frontline diplomacy. Furthermore, Nicolson’s conceptualization of ideal diplomacy as a building block of reputation remains relevant and presents an appealing topic for future research.