In some cases, a new security type may need to be included in a portfolio even though it is not a type that is included in the current security library.
FIA allows this case to be handled by use of the unattributed security type. If a security type is described as unattributed, it still appears in the attribution analysis but no attribution is performed. Instead, all of its performance contribution is written to the Unattributed return category.
This can be useful when, for instance, a new security type has been purchased that has not yet been classified, but its overall performance contribution is relatively low, and therefore will not materially affect the conclusions of the attribution report. Depending on your requirements, you may find this approach preferable to halting the production of attribution reports until the security has been classified.