This paper investigates the implications of the adoption of International Financial Reporting Standards (IFRS) from the perspective of small and growing companies listed on the United Kingdom's (UK) Alternative Investment Market (AIM). We consider the cost–benefit issues of IFRS adoption and investigate its economic consequences. The results reveal that only a small number of comparatively larger AIM companies have voluntarily adopted IFRS for some anticipated economic objectives. The results also suggest that most of the mandatory adopters have done so for regulation compliance purposes and they would not have adopted IFRS if a choice was available to them. As the existing literature mainly covers the impact of IFRS adoption on large listed companies, the findings of this study will give better insights into extending IFRS to private companies. The findings show an association between the early adoption of IFRS and firm size and conclude that size matters in both the adoption and implications of IFRS. This study also contributes to the debate on the implications of the new IFRS‐based UK GAAP for SMEs‐FRS 102, which will replace the majority of existing UK accounting standards for small and medium enterprises (SMEs) with effect from 2015. Our findings have implications for managers, regulators, market participants, practitioners and other stakeholders.