A client works for Company A. The client also is 100% owner of Company B, which owns 2.5% of Company A. The client receives W2 comp from both companies. The W2 comp from Company B originally comes from Company A. Neither of the two companies are service organizations. Is this a Controlled Group or ASG??? If so, why and what would need to be done to make it not a CG or ASG?? Thanks.

Not enough information. Who owns the rest of Company A? What business relationship, if any, is there between the two entities?

I would say that this is the kind of detailed question that shouldn't be answered through a discussion board. Too many technicalities.

Start at 414 and work your way through (B), ©, (m), (n) and (o). I would either hire someone who works with affiliation or go to a technical resource that includes these rules as well as the regular tax code rules.