409(p) Guidance with Subsidiaries

[ERISA-Bubs]

Does anyone know of a good resource for how to apply the 409(p) test when the S-Corporation has subsidiaries and certain participants own stock in the subsidiaries?

The guidance is clear that an option to purchase the stock of a related entity should be counted as synthetic equity. But what if the participant owns the stock outright, rather than an option to purchase the stock? Is that included in the test? If so, is all of the stock in the subsidiary included in the denominator when determining a nonallocation year? I don't necessarily need someone to answer these questions, but if anyone knows of a good 409(p) resource that includes guidance on these kind of questions (even if it costs money), I'd be incredibly grateful.

Thanks everyone.