We examine the work of the International Accounting Standards Board (IASB) on accounting for carbon emission allowances. Despite commencing work in 2002, no accounting standard or guidance has been put in place to date. To understand how a standard-setter defends its legitimacy while not settling this important financial accounting issue, we conduct a qualitative case study of over two decades of archival materials. We investigate nonproduction of a standard as a means for the IASB to protect legitimacy in circumstances where standardization would leave it open to controversy and resistance. Building on institutional research on communication, we show how nonproduction unfolds through four communicative patterns: commitment signaling, equivocal messaging, conveying complexity, and downplaying urgency. Our study provides new insights into how standard-setters navigate difficult-to-settle accounting issues of wide public concern. It also shows how communication shields standard-setters’ legitimacy by prolonging stakeholder engagement and postponing closure on a contentious accounting issue.