This post comes to us from Siqi Li, Assistant Professor of Accounting at Santa Clara University.
In my forthcoming Accounting Review paper Does Mandatory Adoption of International Financial Reporting Standards in the European Union Reduce the Cost of Equity Capital? I test whether mandatory IFRS adoption affects the cost of equity capital using a sample of 6,456 observations representing 1,084 distinct firms in 18 EU countries during the period of 1995 to 2006. I define firms that do not adopt IFRS until it becomes mandatory in 2005 as mandatory adopters, firms that adopt IFRS before 2005 as voluntary adopters, and I divide the sample period into pre- and post-mandatory adoption periods.
My primary analysis consists of regressing the cost of equity (using average estimates from four implied cost of capital models) on a dummy variable indicating the type of adopter (mandatory versus voluntary), a dummy variable indicating the time period (pre- versus post-mandatory adoption period), the interaction between these two dummies, and a set of control variables that include whether a firm is cross-listed in the U.S., country-specific inflation rate, firm size, return variability, financial leverage, as well as industry and country fixed effects. This difference-in-differences design, which includes the population of both mandatory and voluntary adopters over the period of 1995 through 2006, compares the change in the cost of equity for mandatory adopters before and after the mandatory switch, relative to the corresponding change in the cost of equity for voluntary adopters.