Facts: ABC, Inc. and XYZ, Inc. are members of a controlled group. They have separate plans and each plan passes coverage testing on its own; therefore, the plans are tested separately for nondiscrimination testing. There are key employees that participate in each plan (ABC's key is ABC's plan and XYZ's key is XYZ's plan). ABC, Inc.'s Plan is top-heavy by itself. XYZ's is not. Do the plans have to be aggregated for purposes of determining top-heavy?

Yes. See 416(g)(2)(A)(i)(I). And for these purposes, all members of a controlled group are treated as a single employer.