In order to clarify the legal provisions of Law 49/2013 of July 16, the Portuguese Tax Authority through the corporate tax services direction published circular 62/2013. 

Accordingly to the Circular the following tax subjects are covered by the SITC: 

• a) Service providers (they develop a commercial activity, i.e., they perform economical transactions like any other corporation); 
• b) Non- residents with a permanent establishment in the Portuguese territory.  

Finally, the circular states that the list of intangible assets provided in Law 49/2013, of July 16 is purely illustrative. The investment expenses could be qualified as intangible assets susceptible of amortization in company's accounts, as long as those expenses are considered intangible assets for amortization in accordance with article 16 ("intangible assets") of Implementing Decree 25/2009 of September 14 which establishes the legal framework regarding the depreciation and amortization of assets.