PurposeThe purpose of this paper is to examine the effects of adoption of the mandatory International Financial Reporting Standards (IFRS) on the cost of equity capital in a unique Korean setting. In Korea, individual financial statements were taken as primary financial statements. Before the adoption of IFRS, consolidated financial statements were taken as supplementary financial statements.Design/methodology/approachThe authors measure the cost of equity using the average estimates from the implied cost of capital models proposed by Claus and Thomas (2001), Gebhardt et al. (2001), Easton (2004) and Ohlson and Juettner-Nauroth (2005), using it as the primary dependent variable. Mandatory IFRS adoption, the independent variable in this study, is assigned a value of 1 for the post-adoption period and 0 otherwise.FindingsUsing a sample of listed Korean companies during the period from 2000 to 2013, the authors find evidence of a significant reduction in the cost of equity capital in Korean listed companies after mandatory adoption of the IFRS in 2011, after controlling for a set of market variables.Originality/valueThis study is one of a growing body of literature on the relations between mandatory IFRS adoption and the cost of equity capital (Easley and O’Hara 2004; Covrig et al. 2007; Lambert et al. 2007; Daske et al. 2008). According to the results of this study, increased financial disclosure and enhanced information comparability, along with changes in legal and institutional enforcement, seem to have had a joint effect on the cost of equity capital, leading to a large decrease in expected equity returns.