There's a Portfolio Margin FAQ by FINRA: https://www.finra.org/rules-guidance/key-topics/portfolio-margin/faq
Is a really volatile stock also shocked 15% as the index? Some stocks see 15% move daily Are they treated the same way?
For the OCC requirement, yes. But the OCC requires member firms to have higher house requirements for volatile and less liquid symbols. Also, some stocks are not marginable.