HCE Determination with a Stock Deal

[justatester]

I have a plan (plan A) that acquired another company (company B) through a stock deal as of 12/31/08. The participants in Plan B's plan were terminated and given the option to rollover their money to Plan A's plan.

I am trying to determine HCEs for the 2009 plan year. Plan A uses the top 20% rule and it does apply. Do I need to include the employees of Company B. Normally for Stock deals, I would say yes, but since Plan A is not a successor plan I am thinking no. Also, Company A did give credit for prior service for eligibilty & vesting.

Any help would be appreciated.