A. “Financial core” is a term deriving from a United States Supreme Court decision referring to the minimum a worker must do in order to be considered a union member. By this decision, to be a member in a union, a worker does not need to abide by union rules. Instead, a worker needs only to pay initiation fees and periodic dues to be considered a member of the union.
The term “financial core” has been refined over the years and is explained in more detail in The Fi-Core Workbook.
In terms of screen actors, financial core actors pay a percentage of member dues to SAG-AFTRA and they do not have to abide by union rules. This tends to mean that financial core actors do not have to obey SAG-AFTRA prohibitions from taking non-union work, so they can work in both union and non-union acting jobs without threat of union prosecution.