Apparently there are restrictions in how a related party can participate in the retirement plans of multiple companies that she owns. If for example Person A owns an S-Corporation and C-Corporation and both corporations have a 401K plan, Person A cannot fully participate in both plans and is subject to contribution limits (maximum $16K?) across the two corporations.
What are the rules if one business has a 401K and the other business has a SEP IRA? In other words, if the two retirement plans are not of the same type, then how does one calculate and apply the contribution limits across all plans?