Previous research in this field has focused on how countries and companies perceived the implementation of IFRS. The majority of previous research has focused on developing countries with a focus on the auditor's opinion. However, as far as we know, less research has been done on how audit firms work with IFRS based on accounting specialists’ and auditors’ perspective. With previous research in mind, we have found a research gap.

The purpose of this thesis is to study how Swedish Big Four work with new standards, with a focus on accounting specialists’ and auditors' opinion, with IFRS 9 as an example. We also want to examine the importance of accounting specialists' knowledge and expertise and how this is transferred further in the firm, to auditors and clients. 

This study has a qualitative approach where interviews and document analysis have been used to reach the accounting specialists and auditors' perspective. By applying professionalism theory, we have analyzed our empirical data to reach our conclusions. 

The results of this study show that both roles are important and crucial in the work with new standards. The professionals possess high knowledge and expertise that are used in different ways. We have found that transfer of knowledge is a big part for audit firms in the work with new standards, since the understanding of a new standard is created through internal support functions. Our data also shows that the studied audit firms work with good internal support functions to facilitate understanding of IFRS 9 which is considered a complex standard.