Contemporary global governance has become reliant on the expert knowledge of professional actors. Yet governance systems based on technical forms of private authority have proven highly unstable and vulnerable to crisis. How is private authority re-configured following challenges and pressures for change in times of crisis? This dissertation explores the agency exercised by a range of professional actors seeking to legitimately reassert power during periods in which their expert knowledge has become unsettled. A two-prong thesis is advanced. First, in drawing on explicitly normative discourses professional actors seek to reassert moral authority, rather than addressing flaws in their expert knowledge and emphasising their technical authority. Professional actors express attention to and involvement with a wider array of overtly ethical issues that had previously been abstracted away. Second, reassertions of authority may depend not merely on more explicit positioning within normative debates but upon the underlying ideas and values prioritised. The authority of professional actors remains precarious when value sets linked to crisis are continuously emphasised. A genealogical analysis of professional actors in Anglo-American finance since the outbreak of the most recent financial crisis in 2007 is undertaken through a revised variant of the discursive institutionalist framework. Informed by primary documents from professional actors and their associations along with original interviews and secondary media documents, the changing underpinnings of the authority of financial services providers, economists, and advisories based in the United States and United Kingdom are examined. The study contributes to a wider emphasis on the changing authority of a range of private actors as well as to an enhaced stress on both discourse and ethics in International Relations, Global/International Political Economy, and Global Governance scholarship. / Dissertation / Doctor of Philosophy (PhD) / This dissertation explores the persistent prominence of professional actors in Anglo-American finance since 2007. Though their legitimacy has become widely challenged with the outbreak of the most severe period of instability since the Great Depression, the power of these private actors has not entirely been dislodged. Professional actors have sought to legitimise such continued power in financial governance in novel manners since 2007. This study critically assesses attempts by professional actors to reconfigure their authority in the recent period of volatility. In interpreting how professional actors have sought to reconfigure authority, rather than explaining the ultimate success of their attempts to do so, efforts by professional actors to legitimise their power are scrutinised. Uncovering the precariousness of such attempts, this study casts further doubt on the legitimacy of both professionals as well as on-going efforts to reform financial governance that persistently rely on the authority of private actors.