This page is general information, not legal advice. A performer considering fi-core should talk to an entertainment or labor attorney and read SAG-AFTRA's own materials first.
How it works in plain terms
Federal labor law allows union-security agreements, which require workers covered by a contract to join the union or pay fees. The NLRB explains that employees can choose instead to pay only the share of dues used for representation, such as bargaining and contract administration. Those workers are no longer union members but are still covered by the contract. In SAG-AFTRA's language, that's a fee-paying non-member, and in industry shorthand, financial core.
Because a fi-core performer isn't a member, Global Rule One (which bars members from non-union work) doesn't apply to them. That's the reason most performers look into it: they want to take a non-union commercial or indie film without breaking union rules.
What it costs a performer
The costs are mostly outside the fee itself. SAG-AFTRA says fi-core performers can't represent themselves as members on headshots, resumes, electronic submissions, or websites, and they can't participate in programs like the SAG-AFTRA Foundation that require membership in good standing. They can't vote on contracts or run for union office. SAG-AFTRA's position is that fi-core performers taking non-union jobs lower earnings for everyone, and it says so publicly.
What it means for producers
For a producer, a fi-core performer can be hired on a union production like any eligible performer, as long as their fees are current, which Station 12 clearance will confirm. On a non-union production, hiring a fi-core performer doesn't expose the producer to a SAG-AFTRA claim, since the performer isn't a member.
Producers should avoid pressuring anyone to go fi-core to take a job. That puts a performer in a difficult position with their union and colleagues, and it's a conversation for the performer and their representatives.
Common confusions
Fi-core is not the same as must-join, which is a status before joining. It's also different from right-to-work protections, which come from state law and restrict union-security agreements altogether.