Many corporate executives embrace social purposes and connect them to a higher-order rationale for something larger than just the success of their company (Ferguson, 2018, April. 30). And in the Age of Twitter, social media makes it relatively easy for highprofile CEOs to not only position themselves as tech-savvy and approachable, but also to take a stand on controversial issues such as climate change, same-sex marriage, immigration, discrimination and gun control (Men & Tsai, 2012, 2016; Brandfog, 2013; Chatterji & Toffel, 2018). CEOs are not only stewards of their companies but also social actors, and it is no longer controversial to suggest that their communication efforts in the political arena may sway public opinion just like those of prominent politicians (Chatterji & Toffel, 2018). Of course the primary objective of such social activism is to inspire public support around a contentious issue or to address a particular social problem (Salmon, 1989; Deegan, 2001; Derville, 2005; Vegh, 2013), but it seems worth considering whether these CEO political tweets are an effective form of activism, providing new information or raising awareness in a new way. While the outspokenness of CEOs has certainly proven effective as far as grabbing headlines is concerned (Chatterji & Toffel, 2016; Gelles, 2018), a number of researchers have scrutinized the extent to which CEO tweets can be said to be politically or financially effective (Reidenbach & Pitts, 1986; Chatterji & Toffel, 2016; Gaines-Ross, 2000, 2017; Park & Berger, 2004; Gelles, 2018). What has not been tested, however, is the perceived authenticity of CEO tweets. Bearing in mind that the instantaneous, reactive nature of tweets may give a more candid, uncensored understanding of a CEO’s thoughts, this study aims to experimentally test perceptions of authenticity around CEO tweets, using expectancy violation (EV) theory as a guide (Burgoon, 2015). Expectations can be constructed from a mix of factors including CEO characteristics, the history of the relationship between an organization and its publics, and the communications context (Burgoon, 2015; Burgoon, Dunbar, & Segrin, 2002). Traditionally, all violations of expectancy are considered to be negative, since expectancy is thought of as what is socially appropriate and predictable (Burgoon, White, & Greene, 1997; Floyd & Burgoon, 1999). Many EV studies have therefore focused on crisis communications, and suggested that a higher degree of expectancy, once breached, triggers a deeper degree of disappointment, which in turn incurs severer penalties in the form of negative public perceptions and uncertainty about a company’s future performance (Kim, 2014; Sohn & Lariscy, 2015).