During the end credits of Star Trek Beyond, all the producers had their names followed by "p.g.a". This apparently stands for Producer's Guild of America certification.
Are they required to append this to the end of names now, when someone is credited specifically as a producer? Required, that is, by the PGA, as part of a contract or other Hollywood rules?
Or was this just something as part of Beyond's production?
Perhaps this has existed already in films, and I just didn't notice. When it started would be helpful, if it's been long before Beyond.