Edward Lee, Martin Walker and Hans B. Christensen, Mandating IFRS: Its Impact on the Cost of Equity Capital in Europe, look at the effects of mandatory IFRS adoption on the cost of equity capital in 17 European countries (two non-EU: Norway and Switzerland). The sample sizes in different tests are 18,336 firm-years and 18,900 firm-years (in both cases 11% of the observations are for non-EU firms). The period covered is 1995–2006.